A while ago I rebuilt a frame that came to me with aftermarket Mercier stickers on it. It has a fork crown engraved mercier, but on removing the paint I found LeJeune original decals on the downtube, plus it has the willow seat-stay cap. (My decision to put Mercier on it after re-painting, sue me.)
Anyway, it also had a pair of housing stops on the chainstay, one above, one below:
Which I thought must have been a bit of re-work, perhaps when the fork was swapped. However, last night I saw nice touring bike with the same thing. I don't have a picture of that one, but it seems there were others. The bike I saw was a "Mikado Cyclotourer", and there's a pic of another Mikado with the very thing right here on BF:
SO - any other examples?