Samo,
The BUCKMASTER and M9 are two totally different knives. The Buckmaster, model 184, was first developed in the early 80's and is a hollow handle survival knife with two "spikes" on the finger guard. It came with two pouches that could be attached to the sheath and one included a Silva compass. The original Buckmaster didnt have a bloodgroove eather. Later models had a bloodgroove that was imprinted with the knife's name "BUCKMASTER" and didnt come with the extra sheath pouches. I was given one of the early models for my Birthday when I was 16, in 1986, and still have it in the box. I've kept it in NIB condition and its one of my favorite knives in my collection!
The Buckmaster was tested by and issued to the Navy SEALs for a short time, but because of the weight of the system it was shortlived with the SEALs. If you look closely at some of the books written on the SEALS (I can tell you which books and which pages if you like) you can see a few Buckmasters with their silver handles wrapped in black tape.
The SHEATH however was and still is the best diving knife sheath design I have ever seen! The M9 has almost the exact sheath in green instead of black and with the addition of a Bianchi quick release and a wire cutter.
The M9 was designed by Phrobis, I think, and produced by Buck. I have a silver finished Phrobis III M9 and a black finished standard Buck M9, model 188. They are awsome but nothing like the Buckmaster. I dont know exactly how much the Phrobis III Buck M9 is worth but I have been told by others who have seen it in my collection that is it worth a good bit. If anyone out there knows how much please let me know and why is it worth more with the Phrobis III stamp??
I hope I was of some help...