If your M1 Pro is the base model configuration, ignore my advice below.
One BIG piece of advice. Before you trade in, make sure you have an original receipt of your trade in that clearly shows the full configuration. When the trade in warehouse receives your MBP, they may claim it is a different configuration than what you submitted and charge you the difference. Some custom configurations still show up as the lowest end version when the serial # gets scanned. It will not matter if you trade in via Store or via shipping because the central warehouse has the final say. This happened to me last month on my M1 Max which the warehouse claimed as an M1 Pro and lowered my trade in value by $300. Fortunately I had my box and original receipt but it took 4 phone calls and finally to a top level supervisor who was able to correct this issue. It is the supervisor who told me that the warehouse system scan does indeed say M1 Pro even though my receipt and box clearly show M1 Max. I also saved a screen shot before of the "About this Mac" but didn't need to submit that. My example is probably the most extreme difference but don't take a penny less than what they promised!
In store is still a better choice because that will rule out any functional and/pr cosmetic issues that affect the trade in.