Serial numbers yet again

[1025rtlb]

OK boys, Just purchased my first lowboy and need parts. So here is my situation. Left front tag is washed and can barley make out numbers. I think it reads 23340x. Engine number is 284153x. The engine has been out and repainted and was told it was a rebuild but may have been a swap. Here is the big question, are there any other clues to look for to verify my eyes are reading the chassis numbers correctly? I have researched this and think it is a 72. Are there changes to the tractor to help me verify?
I am sure this is one of many hurdles I will need to jump so be patient with me.

[outdoors4evr]

Clean off the serial tags with paint thinner. Perhaps do a rubbing (paper and use pencil or crayon) and make out the numbers.
Look in the serial number database to see where your tractor and engine falls.