Greg, does the pension have Wickliffe's exact date of birth?
In my "Colonels" research, I've used the Mexican War pensions extensively. I know of dozens of examples of former Confederates applying for and receiving a Mex War Pension, "Old Army" pension, or "Indian fighter" pension. To give on KY example, Major M. D. Logan of the 3/7h KY applied for a Mex War pension. Colonel John S. Fain (65th GA) had an extensive 20-page typed history of his Mex War service in his Mex War pension file.