GURPS 3rd.ed. cover's history

Hello!

I am trying to understand GURPS 3rd. ed. covers. I am updating a post about GURPS history. Can someone help me to discover when this covers were printed?

Covert Art 1 in Dark Blue + Grey:
Cover 1 = 1st printing 1988?

Cover Art 1 in Black + Yellow:
Cover 2 (1st from left) = 2nd printing 1989?

Cover Art 2 - no border:
Cover 3 (middle) = 3rd and 4th printing 1991?

Cover Art 2 - with border:
Cover 4 (the last one, right side) = 5th to 8th printing 1992?

Covert Art 3 (by Jeff Coke):
Cover 5 = revised edition, surely 1994 (Thx to Gollum)

GURPS 3rd.ed. cover's history