I believe the P/N for these is 64910-99. I've had a set on my '04 Road King Classic for about 4 years. I love the sound and wanted to put them on the '81 FLT I just bought. Not sure what I'll have to do to get them to fit but I don't care, I want that sound which reminds me of a 50s or 60s automotive glass packs.
These mufflers have less restriction than stock mufflers so will work for a stage I upgrade (high flow intake and exhaust).