Here are some photos of my sample T2 machine

http://gallery.myhomegameroom.com/gallery/t2_sample

It's been torn down completely and rebuilt. It plays well, it's just ugly

Unfortunately, the samples and protos were not diamondplated, so the playfield is beat. The cabinet is rough as well, and the artwork is different on protos and samples than production games

It's a neat piece of history, which is why I kept it, and why I spent 100+ hours reconditioning it.

Yes, there are a few other little differences, too.

As you mentioned, the speaker grilles are 'W' logos, not solid red.

The backboard decal is missing - wasn't installed on samples or protos. Same for the underramp decal on the right ramp. The ramp had no protectors - I got a set from a partout and put them on a new Pinball inc ramp, as the original was just destroyed. The metal bracket under the H/K ship was flat, no 90 degree bend like production.

The gun handle was made using a different type of casting compared to production games.

Some colors on the playfield were different. Some lettering on the lower cab is different. There are probably other minor things I'm forgetting.

Is your game level from side to side? Mine tends to bounce off the post and then back up to a flipper bat.

3 slots is a european coin door.