Border Guard Camoflage Uniform

[Al-muell]

Left to right:
1.Modern Belorussian PV (2002?)
2.Late Soviet PV (1989? Camo pattern no longer in use in Russia as far as I know)
3.Soviet PV - and here's the question: What period can it be? Buttons are not dated and there's no stamp (there is a trace of some label that was removed). It was certainly worn for a long period.
The differences:
1&2 have all buttons "hidden", and both have shoulderboards, while 3 has the buttons always visible.

type of buttons (see next pictures - note that there is a difference in attaching between Soviet - horizontal- and Belorussian - vertical).

Space between shoulderboard and the collar in 1&2 (they are almost the same size)

I would appreciate any help