The dual clairifier is a very nice touch
from the pic's it looks like it's opened for RX/TX . Do you know what the power ratings are on AM and SSB ? Have you hooked her up yet ? Does it seem at least ballpark alighned to you ? closest to center slot will do on the duals (it doesn't have to be perfect , just needs to lock down and stay on freq which those radio do a fine job at) they do like a slight warming concerning SSB all the same. (most do)
I see now where it says you haven't even hooked her up yet. Depending on how the TX/RX was opened up , that baby could have a 20 Khz slider on it , although touchy , it will get the job done nicely. If the radio has a (call it what you want) NPC mod , it would DK 1 to 2 watts and swing 18 to 20 on AM which would be pretty good for your TS350.
The radio could swing it's full power on SSB and the TS350 would handle it just fine. If you can find out what your AM side is doing and as long as your as low as 2 watts on DK , you should be fine. Otherwise , you can just send it off to your favorite tech and have him go through it for you.
Always nice if given tech could have both radio and amplifier when he does his alighning , but I think most would know how to set up ballpark for a TS350. Like Mole said , these are also my all time favorite cb chassies , always known for there great receive sections in them.
I will also agree that not alot needs to be done to these radio to perform well right out of there boxes new. There's really no need to bore these radios out , but guys tend to like what they like no matter what somebody else thinks. It looks like you have a good one Steve , but I also think it might be to your best interest to hook the baby up and give her a work out , the mods on the radio from what I can see are not a hack and whack job , they have been around for a long time.
As always , the best of luck to you and I hope you find some enjoyment out of your new (to you) Grant XL . Peace