97HT could be either F4, F5 or F6 depending on the model so you're good there. It also says it was originally six cylinder.
The serial number 171493 is low enough that it was built in February or March of '49.
It's possible paper from another truck was used to title it, but you can find out for sure. Look on the passenger side frame rail up near the diagonal crossmember. They are stamped lightly so you might have to sand or scrub with steel wool and then shine a strong light across the top of the frame. You should see the number - with a hollow star at the front and back of the number. Some have the whole vin, others only have the serial string of digits.
Let me know what you find and I can help you sort it out.... Tim