It's mostly inference
That’s what I figured. To be clear, I have nothing against LAMs. But since the Clans did have something against LAMs for a couple centuries, I do find it hard to believe that the Clans would resurrect LAMs for the Goons’ mission.
but we do know that Clan Wolf equipped the Dragoons from SLDF Caches. We also know that the Goliath Scorpions trained the Dragoons in SLDF tactics to an ability that they could stand up to frontline Clan Units. And we know the SLDF used LAMs.
After they discovered LAM pilot in the Inner Sphere, it may be that the Goons asked for LAMs and LAM parts from Brian Caches for their resupply runs.
But I find it unlikely that the Clans, even the spec ops-ish Scorpions, kept LAMs alive for a couple centuries given their phenotypes and how they siloed training according to those phenotypes. If the Scorps did keep LAMs alive, then we’d have some Clantech LAMs from the Golden Century or such, and we don’t.
I think it’s much more likely that the Goons attracted and sought out LAM pilots in the Inner Sphere after the Goons found out that LAM pilots still existed there.
There's also the large number of LAMs listed in the Wolf's Dragoons Sourcebook. The number could be even higher before the Dragoon's supply runs. Plus with LAMs being hard to get in the IS I can't see the Dragoons showing up and buying them.
The WDSB dates from 3030, and its TO&Es are before/after the Battle of Misery in 3028. By that time, the Goons had been in the Inner Sphere for 23-25 years, a quarter century, and worked for every Successor State. That’s plenty of time to collect some LAMs and LAM pilots from across the Inner Sphere.
(I’d also note that those TO&Es date from when the Goons were finishing up their time in the Draconis Combine, the one Successor State that still had an operational LAM parts factory.)
And for those LAM pilots who were dispossessed or could not repair their damaged LAMs, the Goons would have been a special draw as the Goons could provide LAMs and LAM parts from Homeworld Brian Caches. I would guess that’s where most Goon LAM pilots came from. LAM pilots, especially the dispossessed or those with broken LAMs, would have flocked to the Goons if the Goons proved that they had a steady supply of LAMs and LAM parts.
It also takes time to train so that would have been harder to do. The Dragoon personnel would have to be highly trained in order to do that so I can't see the LAM pilots getting trained in the IS and being rookies.
The Scorps/Goons didn’t need to train any LAM pilots for the Goons to field LAMs. The Goons did hire in the Inner Sphere, and there’s no reason to believe they wouldn’t have hired some of the Inner Sphere’s LAM pilots.
Kurt Brunner was born as a Goliath Scorpion and underwent trials to join the Dragoons. TRO:3085 He was a Stinger LAM Pilot. And since the Dragoons rarely if ever hired outside mercs I don't see all those LAMs being piloted by IS personnel.
That’s the one bit of canon that opens the door to the possibility of Clan LAM pilots. But it doesn’t say definitively where he got his LAM training, as part of a regular Scorp LAM program in the Homeworlds or with LAM pilots in the Inner Sphere.
I could maybe see a Scorpion LAM cross-training program for freeborns that qualify for the Warrior Caste since they don’t have a phenotype and would care less about the stigma of being neither mechwarrior nor pilot. But the fact that Brunner is trueborn (Shaffer bloodname) and apparently has the mechwarrior phenotype would seem to throw cold water on that theory.
Think I’ll post on Ask the Writers and see if we can get a little more clarity on this. I’m guessing the writers just never thought it through when writing up the TO&Es in the WDSB (details on the Clans didn’t exist then) or the Brunner entry in TRO3085 (oversight). But we’ll see...