Hey guys, I am new to this forum website and just asking this questions because I am new to collecting figures and I came across my small incomplete collection of Vintage GhostBusters figures. So I wanted to know if there are variants or were there just a one release original wave. Thanks much appreciated! 
This is a comprehensive source of information on the vintage Ghostbusters figures:
https://ghostbusters.fandom.com/wiki/Kenner_The_Real_Ghostbusters_Toy_Line
One of the most noticeable variants is in the figures’ Proton Packs. Originally in their first release, the Packs were molded with the hose exiting the bottom of the Pack (similar to how it does in the cartoon and on the film props), whilst later iterations have the hose exiting the middle of the circular Cyclotron:
Thanks so much for the info kingpin! Much appreciated!
Thank you so much
The Slimed Heroes Ray Stantz came with his accessories molded in two colors, as I recall.
Green Ghost with Proton Pack (Slimer) had two versions: blue pack with red gun, or red pack with blue gun.
Seems like there was also a variation on the Finger Pop Fiends, but I can’t recall it off the top of my head.
Alex