buck m-9 question

[nolesfan1]

I recently found a buck m-9 at an auction and bought it not really knowing anything about it. But the price was right at $15.00. It has BUCK 188 USA> on one side, and M9 PHROBIS III U.S.A. in three lines on the other. Then about a week ago I bought another one new in the box with all the papers on e-bay with BUCK 188 USA> on one side, and M9 PHROBIS III U.S.A. Patent Pend. in 4 lines on the other side. Now from what I have read on here both have the same date stamp of > which is 1987 . But why does it differ on the other if they were made the same year. Sorry for being so dumb. Thanks

[porterkids]

The first M9 bayonets were marked without the "PAT. PEND." It was later in 1987 that they changed the blade marking to include it. That's why you'll find both the three line and four line markings with the 1987 date code.

[nolesfan1]

Thank you, I appreciate you takeing the time to answer!