AC Help on 87 Wagoneer

I was getting ready to hook up my manifold gauges to my sons 87 AC and I couldn't find the scrader valves on his compressor or lines to hook up and check pressures. Any idea what I'm missing? There is a sticker that says his AC used R12 or R-134a so I was thinking it'd be like my '96... but it's not.

Here's a pic... anybody have any ideas? I know my manifiold gauge kit is for R-123a, and I don't think it'll hook up here.



thanks.

the A/C compressor is r-12 and when you get them hooked up make sure you losen the valve nuts. the rods on end.