This looks very similar to N#284504 but it is different in some ways, notably the protrusion in front of the buffalo's feet. I purchased it in 2008 from APMEX as a generic, and do not see any mint marks, nor did I see an exact match in the catalog though I may have missed it among the many buffalo replicas. Dimensions are 39mm diameter/2.9mm thickness, 31.1 grams, and otherwise very typical of generic bullion. The tube the round came in is generic and has no markings. Perhaps a buffalo replica expert knows more about this one than I do.
