Tips for buying a used Rectifier 4x12

I am looking at buying a second hand Rectifier Slant Cab and am looking for a little advice. Mostly, what could go wrong, anything specific I should look for that could have failed or is failing.

I am being offered for $600 CDN
Mesa Rectifier 4x12 Slant Cab w/V30's
Original parts, original slip case
no visible damage
bought 7 years ago
used about 300 hours a year, just about 2200 hours of use in its life.
One tour for a few weeks and several local shows

It appears on the outside like a great deal, and no I haven't played through it yet (hopefully on the weekend). Lemme know what you think I should be paying attention to!

First, look at general condition. If it's dinged and scratched, that tells you a lot about how well it was cared for. How clean is it? Is the grille full of dust?

Look for any evidence that the cabinet has been stored in a wet or humid environment. Look for any peeling or bubbling of the tolex covering. If you can see the speaker cones, look for staining. Check the cabinet over for softness that could be delamination or rot.

Look at the metal hardware for corrosion, including jack plate and jack hardware.

Look for evidence of speakers changed out.

Listen carefully for signs of buzzing. This can be frequency-dependent, so play every note on your guitar through it. Listen for odd low-end rumbles or distortion or lack of low end that could indicate blown speaker or miswiring. Listen to each speaker to see if you can hear any that are low volume or are not making any sound at all.

If it looks great and sounds great, it should be fine.

Good luck!

Good advice there