how do you identify a 1987 442?

[xitabl442]

The VIN tag riveted to the top of the cowl on the left side should have 442 stamped into it. GM used unique hollow center rivets for these that are difficult to duplicate. If that plate has standard rivets in it there's a chance it's been replaced.

 

[Blake442]

The VIN tag riveted to the top of the cowl on the left side should have 442 stamped into it. GM used unique hollow center rivets for these that are difficult to duplicate. If that plate has standard rivets in it there's a chance it's been replaced.

Every g-body I've ever seen or owned (9) has had the cowl tag attached with either phillips head screws, or a 6mm hex head screw. The vin tag on the corner of the dash is riveted on like you said.

The cowl tag will have 442 stamped in it.
The VIN tag will have the '9' in the 8th digit.