Well, I went out and checked..My PP375 has the exact same metal to metal setup as the 4000 uses. Like the picture above. Which makes sense, since all the rest of the parts on the PP375 & 395 are the same as the 4000. Side outlet on muffler, high top air cleaner setup, heavy duty recoil, etc. These were the last of this line of saws.
As far as the filter cover being vented or not. All green Poulan 3700's were black and slotted as far as I know. The red Craftsman 3.7 version had black non-slotted cover as I know. Now, as many of these saws, in all their versions that were made over the years, you are likely to find many parts that have been changed, swapped, cobbled together, to keep them going. Just about everything on them will interchange parts amongst them. The only things that have to match, are the piston/cyl. Recoil match up with dogs on the flywheel etc.
You can build just about any combo of a saw from all these models. Which I have done by the way. LOL
I put together a saw from spare parts I had, for a friend of mine. The crankcase is from a 3.4 Craftsman, recoil parts from a 3400, rear handle was from an early 3400 with the small hole rear mount, that i drilled out to accept the "hex" mounting bolts etc. Its just a mish-mash of parts. So you are likely to find most anything out there, that people might have cobbled together. I'm sure I'm not the only person to have done it. LOL Dang things runs real good too!!.
Gregg,