I doubt anyone would mistake a moose antler, even a small one, for anything else.
Reindeer don't have much in the way of palmation. Rather less than caribou. If one were to find antlers in a UK car boot sale, chances are they are from a UK source, and if they show palmation then chances are very high they are from fallow deer. If someone at a boot sale told me that the particular antlers they were flogging were reindeer, I would take it with a double handful of salt!
Reindeer, typically, has much less in the way of a porous core than other deer, very dense, but you would have to be looking at sawn up sections to see this. Moose too is very dense, but on a whole other scale.
While you might be able to collect samples, I don't think they are necessary, or even necessarily your best bet for using as reference. Even within a species, looking just at mature specimens, there can be significant variation in form, shape and size. Best you can do is look at the antler to be identified and try to fit it to as many broad characteristics as you can. Doing a one to one comparison with your "reference" set might work, but how will you handle variations?
For telling the difference between muntjac and roe, you need no more than Google for images of the antlers or skulls of both and spend a little while looking at the dozens of example photos. They are very different.
