Well, Im far from a newbie . . . . the top mounts were a pain and were somtimes cut off . . . I've got a Blaster mod pipe with no top mount just for that reason.
I have to admit I missed the seam in the picture . . . if I'm not mistaken the "early mod" pipe to which you refer is the same Limited pipe I pictured with about 1.5" cut out of the center of it just like the way they make the Limited SJ pipe into a Mod by shortening it. . . . . . Do you agree ?
If the pipe Fly2day has is a center bleed pipe then I don't know what it is . . . . .it must be something really oddball that was cut up, rewelded and then recoated. Alot of experimenting went on "back in the day" so it may be something "custom" .
Since we're talking about 'Blaster pipes . . . . . . There is another unusual Factory Pipe chamber floating around out there that you guys may run accross some time . . . . . it's a FPP 'Blaster MOD MOD pipe . . .that's a standard "wrap around center bleed 'Blaster Mod pipe" with a section cut out of the middle of it and then rewelded. If I recall correctly, this shorter "mod mod" pipe is actually the one that Tim Tynan's TNT pipe is based on. They were primarilly used on strokers.