I disagree - there was no, or very very little, weapons lostech available. Comstar aggressively destroyed or seized even the smallest amount of it. I think the best illustration of this is what an outlier Wolf's Dragoons was for having been rumored to have star league technology in its mechs.
That's funny, because I use that same example to illustrate exactly how little Comstar cared about lostech weapons (as opposed to manufacturing, or databases).
Think about it, the Wolf's Dragoons was already an outlier because of it's size (far more company sized merc units than there are units 5 regiments strong), so they should have been on Comstars radar already. Then rumors start going around about them having found a cache of Star League gear to get them started and Comstar does fairly little about it. They investigate, sure, but do they arrange accidents? Do they sweep in with a few hundred ROM agents and kill them all in their sleep?
Nope.
They way I see it Comstar has 2 mayjor objectives.
1: manipulate technology in the way we all know and love.
2: keep quiet about it so the Houses don't gang up and crush them.
So you have to ask your self, is a small merc unit walking around with a bit of lostech that's bound to be destroyed in battle in a year or two worth the risk involved in launching an operation to destroy such tech and risk revealing themselves? Or would the wiser course be to simply sit back and observe until the very nature of war does your job for you?