Typically all that matters is thread pitch and maybe OAL if the magnet is likely to come close to something like the rotating assy. But in 99% of cases any plug with the correct thread will work just fine.Looks to me like Dimple might be out of business. Votex doesn't make a drain plug for Buick Park Ave.
So for a quality American made magnetic drain plug for a Buick Park Ave, Goldplug is the only option that I know of.
Best I can tell many of Gold Plug's variations like MP-02 vs MP-02T are just for hex head size, and I don't particularly care what socket my drain plug takes. On personal vehicles I often write it on the front clip/radiator cover (along w capacity) so one could always amend their notes.