I doubt it. My chocolate mint has a definite chocolate undertone. My pineapple mint has a definite pineapple undertone. I imagine the lemon and orange would be distinctly different.
I think it depends on the particular plants in question (it is certainly possible that, somewhere, the same plant is sold under two names), and also on the particular nose doing the sniffing. I can tell you that wandering through the mint section of Richter's greenhouse aisles, there are a couple mints that to me smell absolutely identical but my sister says they are quite distinctly different from each other to *her*.
I don't think it's really something to worry about. Ideally you'd smell a particular mint plant before buying (catalog descriptions are really inadequate to convey what something ACTUALLY smells like); if not, if you have to mail order, ya pays yer money ya takes yer chances and they're not THAT expensive a plant