Insurance "Agree Value" vs. classic insurance appraised value

[ADY]

I'm trying to consolidate all my insurance policies and curious how much I can expect to get hosed by my insurance company (USAA) if I opt to add my 1968 Camaro to my existing policy vs. keeping my Hagerty 'agreed value' policy in the event of a total loss. Have any of you had your classic restomod totaled by your insurance and if so did you feel you got a fair payout? Realize this can vary widely based on the insurance company and their appraiser, but just trying see if in general people have got a decent valuation.

thanks,
-Adam