One other item I just recalled, not really an issue but something to be aware of. The 3PH back then had a different design and didn't lift as high as the current BXs so you could have more issues with taller attachments like post hole diggers designed for current sub compact tractors, etc.
As an owner of a 2005 BX, I've heard that before but always thought the 3 pt setup was properly sized for the tractor itself. Little tractors do have limits on the size of implements, but I've been using a standard, full-size Speeco auger on the BX for years without any problems. Standard Cat I carry-alls and fert. spreader also work fine. Haven't tried the 6 ft. tiller, 6 ft. box blade, 7 ft. scraper blade, etc... doubt they would work, even if the pins fit.