There is only one version of the clutch that goes between tailgate handle and regulator. Same for both Blazer and Suburban.
Im quite sure I have some here in one of my junk boxes. I'll measure if you like.
And for those with later Subs and rear window issues, this is a good site:
https://www.tradecraftspecialties.co...wMotors#Topic1
* You said you got everything from LMC...regulator included?
I'm thinking you got a Blazer regulator in there. Sub regulators are shorter across than Blazer.