speaking from about 20 req hours recently :
I have never seen LSes run out (theres almost as many as rail lights in req bruh), or any attachment other than MH BC and gyros (lowpop rounds with people wanting to do gyro shotgun memes)
b8s are also not viable at all lmao
if any attachment was to run out of stock it would be qfas and bfas for their relative popularity with qfa being frequently used on m41 and L42 builds and bfa being used on m41 meta build, m39 builds, hpr builds, and being generally a low stock attachment.
the main things req runs out of are brown/black webbings, pyro kits, heavy revolver ammo, the obvious AP ammo, aforementioned BCs and MHs (although mh is offset by pointman kits)
luckily the BC is generally used on burst builds now rather than being a straight buff to every single weapon it was applied to.
the current attachments that need buffs, in my opinion, are
- the EB, since currently the RC is a straight upgrade in all situations
- bipod (being worked on)
- arm brace (being worked on)
- supressor, maybe (stealth is kinda useless when benos have thermal vision)
- the vertical grip