Just wondering if the two are interchangeable as far as thread size?

The Ruger GB guns we see that are older are 9/16x24 RH thread.

The new replica versions made by Ruger (the ones I have anyway there is a long version and a shorter version) are 1/2x28 which is the more common thread for 223/5.56, etc

When I chopped by GB down to AC556K length SBR, I switched to the new style Ruger Flash Hider in 1/2x28 simply because direct thread 223 suppressors are more abundant in that thread.  Yes, its not original but I do not care.

I have no suppressor options, so bear that in mind.  If one. has a sound suppressor, naturally one wants a rifle-mounted Flash Suppressor that adapts well to the Sound suppressor.

When choosing a conventional Flash suppressor for 5.56 rifles, I find myself using an A2 style Flash suppressor.  Does everything well; Reduces flash, limits dust signature, and reduces muzzle rise a bit.  Usually dirt cheap, and maybe free if you already have one.

There are other muzzle devices out there that are more specialized, or perhaps do one thing or another better than the A2.  AFAIK, none of them do everything as well as the lowly A2.

If one has neither a flash suppressor, nor threaded muzzle, the slip-over Choate unit has an A2-style FS configuration, as well as a much-improved, winged, military front sight.  They are offered in different I.D. measurements, to suit the different O.D.s of various barrels, as well as blued and stainless steel.  Disclaimer: no financial interest.

YMMV