Can I verify that OFP is installed correctly?

Well, yes, but only for OFP versions up to 1.20. BIS put out a little OFP installation verification program, CheckOFP, which you can download from here. If you're still back there, you can run CheckOFP and see if it detects any errors.

If you get the following messages, don't panic:

Error found in file AddOns\SU25.PBO (42efdc11!=e8965a02) 
Error found in file AddOns\TRAB.PBO (26ffd21a!=92577b72) 
Error found in file AddOns\VULCAN.PBO (f0ec93a8!=0e112b4a)

As BIS admits, this means that that the copy of the version 1.10 upgrade that you installed had some minor kinks in three of its addon files that are hardly noticeable anyway.

To eliminate even the slightest trace of these problems, download the version 1.10 ultimate upgrade patch from here and reinstall. When you run CheckOFP again, the error messages should no longer appear.