I do not have the funds for a machine shop. Is there a way to do something like this myself?
Not really, all you can do is check to see if it is flat with a straight edge, or a flat surface and feeler gauges.
If it's not flat there is no use in putting it back on without flattening it. I suppose you could take a file to it, or a grinder, but you better have some time, a steady hand, and a good eye, and a good way to check it as you progress, or digress.
Having it done at a machine shop is the proper way to go about it, and I suggest you save up to do it right the first time if it does need to be flattened, which is likely.
Grigg