Not sure when they started producing those, but I know Thrush produced those mufflers into the mid 1980's.
I sure wish they'd bring them back into production! I'm sure they flow
below horrible and cost a ton of power, but they're one of the best-sounding mufflers ever.
I picked up a pair off eBay over a year ago just to have them laying around in case I ever had something to put them on again.
Aaaahhhh...such fond memories of my youth lol.
As far as "would they be correct for a day-2 deal"...I say "who cares!"...run `em!
Eric