I think this muffler tip is from a late 1980s BMW (528 or 533 maybe?). Bought it at the BMW dealer back in the mid-1990s. IIRC, it was a little too long, so I shortened it a little with a pipe cutter. The rolled end was similar to the ones I saw on 911s back in the early 70s.
Click to view attachmentThe tip slips over the tailpipe; two "dimples" on the underside provide a friction fit. I drilled a small hole through one dimple and drove in a small stainless screw "just in case." The tip has been on the car for at least 25 years now, so the chrome isn't as pretty as it ones was.
Click to view attachmentSorry, I couldn't find a part number.