The old Tamiya M26 Pershing may correctly represent the old WW2/early Korean War versions, but the kit has a number of problems and the Hobby Boss kits are better. Problem is, I haven't found an original version with the early all-steel tracks and original-type barrel. Is there one, or can any of the existing ones be modified? I did see a couple of pilot versions with the old-style track, and I have a set of metal aftermarket replacements.

the Tamiya kit is the M26 where the Hobbyboss kit is the M26A1
the difference is the WW2 M26 has the single pin tracks where as the Hobbyboss M26A1 has the double pin T80 metal chevron tracks and the M3A1 90mm gun which had the bore evacuator and a single baffle muzzle brake
also the Tamiya and Hobbyboos M26 kits the parts are interchangeable

https://www.scalemates.com/kits/hobbyboss-82424-m26-pershing--106748

As far as I know HB does not offer their standard M26 with steel track - only the later chevron track as seen in their M26A1 kit. Some of their T26E4 kits seem to have the steel track, but you'd need to look at the sprues to see if all the standard M26 parts come in the box. (Try https://www.1999.co.jp/ to see the sprues...)

But FWIW there isn't much wrong with the Tamiya kit that can't be fixed. It lacks some casting marks (Archer transfers is your friend there) and the suspension is a bit gimmicky (just glue it!), but otherwise it's ok for a WWII beast. I think you do need to carve off the angled bracing on the back of the final-drive units because it was added after initial field experience so wasn't on the WWII Zebra Mission tanks. Terry at PMMS says the turret bustle is a tad narrow, but having looked at both Tamiya and HB kits from my stash you'd be hard pressed to see it.

They don't. The Hobby Boss T26E4 #1 vehicle has workable single link track, but the upper hull is not an M26, it is the T26E1 prototype hull with recessed grab handles on the engine deck. The turret also has the loader's ring-type cupola. You can build the first Super Pershing from the kit, and that's it. Or you can buy an RB Models 90mm M36 replacement gun barrel, leave off the counterweights, turret equilibrator spring assemblies and applique armor, and build the prototype T26E1 as it appeared in early 1944 (that hull and turret was reused for the first Super Pershing). The kit's serial number decal can be used.