XC6820 PIA Engineering Sample

I ran into this chip recently, and the collector obliged to send me these hi-res images.
This "XC" 6280 PIA is an early engineering sample chip from the 20th week of 1975.
This chip is gold + ceramic. Note, no grounding strap across the top of the chip which you see in later chips.

Compare it to the chip from 1976 found on my Mimeo-1