Rear axle identification

I have searched 442.com and found conflicting information about my rear axle in my 80 cutlass t-top. I have gotten under the car and it is a 10 bolt cover with a silver "LSD diff lube only" tag on the lower right corner of the diff cover.

Is this the often sought after 8.5 rear end, or is it a standard posi from something else? Are there other numbers I can use to narrow it down?

You would normally not have the 8.5 in the regular 80 Cutlass, to be sure remove the rear cover and measure the ring gear.