Hello.
I have recently purchased my first roller lock firearm - a lovely 9mm MP5 reverse stretched styled PDW made by Getz Firearms.

I am trying out different stocks with it - it originally came with a retractable stock - and have noticed that some come with buffers & others do not.

Seems like all the retractable stocks, regardless of mfg. comes with an H buffer installed. A2 stocks do not have a buffer. End caps/pistol caps well it starts to get confusing German made do not have a buffer while the US made ones do. B&T folding stocks also come with the buffer while the Blackthorne clones of those stocks do not.

I have just picked up a Blackthorne made B&T styled folding stock copy that the seller listed as a HK93 stock. I got it for dirt cheap ($50 shipped) & bought it since the real B&Ts were sold out everywhere & it will be a few months till they are in stock again.

Now the stock had some old epoxy in the cap where a buffer was previously glued in.

I do not want to damage or cause excessive wear on this firearm. Will it be fine without a buffer or should I mount a new one in? No plans (ahem, $$$ for) full auto & probably will not be using a suppressor with it. 115gr 9mm mostly.

The HK94/MP5 does not require a buffer in the stock.  The MP5 A2 stock also fits the HK93 which needs a buffer in the stock - hense the H-buffer.

Mount the buffer, OP.

When in doubt...go with the buffer.