As noted, the Core itself spread over the years.
Grayson made it available to both FedCom nations right away & also gave a copy to Ricol.
Ricol gave that copy to Teddy IIRC some time after the Ronin War IIRC? 3034-3036
Teddy shared it w/ the KapCon partners sometime after that I think in the 40's.
The Cappies shared it w/ the TC & MoC in the 50's.
I think the OA got some at some point before the Raven's arrived but not on a ton of their units till the Jihad.
The Periphery certainly wasn't making TRO 3050 mechs in 3050 for sure.
I think the real issue is how quickly each nation digested that core & put the tech into production.
For example, the FC was researching Proto-DHS & CASE before the 4th SW IIRC, prior to even having the Helm Core, but, it took them till 3040-42? to figure out how to mass produce DHS internal to the Fusion Engine.
We have full on production grade ERPPCs on the Marauder-5D in 3047/8?.
But does that mean the ERPPC was common to the IS? Not likely.
The factory probably made less than 2 dozen a year so by 3050 you had what, 2 battalions of Mad-5Ds across the entire IS?
Most of them probably in A-Rated house units & not out to Mercs, Militias, or C-Grade commands.
And that is the real thing. With 20K+ Mechs in the FC. A few Hundred produced in the last 3 years before the Clan Invasion still only gives you, what, 2% upgraded status?
And this is the most advanced house in the IS.
So its not like it went from "Never seen" to "Everywhere".
Its more like, Oh, yes, there are some "small #" of examples out there but most of them are deployed at/near the factories or capitals with only the best units.
Heck, some Houses were still producing intro tech into the 3060's on some lines.
For example, the Stinger line on Coventry didn't get upgraded till 3067.