I will check the three I have at home for their distinguishing characteristics.
I can't seem to figure out what you mean with "spacer on Philips"...
There is one more possible variant I can think of to this range that I haven't seen yet. It would slot in between the 1986 and 1989 models above. This variant would be from 1987/88 and have a large "V" tang stamp but still have the brass spacer on the Philips layer.
My third, which I'm keeping in unused condition, is the same configuration except it has a big V. Everything else is the same.
Also, all three appear to have the same profile on the combination tool.
Maybe picture this will help. For the old grey mag glass/Philips, I know of three different backspring spacer combos they used:Type I: 1973 - c.1982. This is a flatter spring that largely follows the same contour as the scissors spring. It goes under and not around the #4 (fulcrum) pin. Type II: 1982 - c.1987. Same spring as Type I, but they add a small brass spacer around the #4 pin on this layer for extra support Type III: 1987 - c. 2006. The spring is completely resigned to have a bump in the middle that rises up next to the #4 pin. This eliminates the need for the brass spacerThe backspring is completely redesigned in the early 2000s for the new clear mag glass/locking Phillips.(Image removed from quote.)All factory Scientists (i.e. excluding the +B version from 2009) were made between 1986-1999, so they will either have a Type II or Type III spring in them.