Yes.
#1. Using Hex numbers is faster than using decimal numbers (talking here about execution of the same number 1.000.000+ times).
#2. Replacing dec/hex numbers by variables slows down execution, but in turn does not need the resource direct numbers precache (talking here about bites).
#3. DllCall is faster using hex numbers (talking here about numbers bigger than 2047=0x7FF=11111111111)
#4. Within an array makes sense using same type of numbers (talking here about addition & subtraction within an array element).
So use hex/dec numbers when possible, but replacing them unnessessary unless you totally rewrite everything for performance reason.