Yup, early production mag tank. I believe the cylinder has been off (no way to confirm though), so it's possible, maybe even probable that the piston/rings are replacements.........plus the piston was in backwards. (arrow pointing towards intake). I should post up some pix on the tear down, I did post up a thread on a difficulty with the clutch removal ("028 clutch help" maybe?), this is the same saw.
I have someone that may have a donor for me, if I get stuck on the muffler I'll let you know. Thanks.
Take a close look at that piston.....I worked on an 028 recently that had the piston stamped wrong.......The arrow was pointing toward the ring gaps.....Just make sure the ring gaps are on the intake side.