Have you dropped the hammer and bought this yet? If not, you will miss out on a nice rifle at a deceit price.
As I understand, OP never had a chance to buy it Don't rub it in
There are people that say they can tell an original from a put together correct Garand. I certainly am not one of them. I assume they can tell based on wear and other signs. However I don't see how they can be 100% accurate. I would enjoy seeing a blind test done. Give an expert 5 Garands that are put together correct and original and see if they can tell which is which.To be clear, there's no such thing as an "all-matching" Garand. There is such a thing as a "correct" Garand. There are something like 57 components, most of which bear a drawing number and/or a heat lot number that would need to fall within a certain serial number/date range to be "correct." There is no way to tell if a rifle is "original" - I think that finding an "original" M1 Garand would be highly unlikely. A correct WW2 Garand in nice shape is worth much more than $800. Anything else is, generally speaking, worth no more than the price at which CMP is currently offering mix-masters in similar condition. People want the CMP certificate when it comes to a mix-master.
Please be careful about your terminology, and what is being represented. Terms like "all correct", "all original", and "all matching" get used as interchangeable when they are not. On a USGI M1 Garand receiver, the serial number will tell you the date of manufacture for that manufacturer. All the other numbers you see are "drawing numbers", and may or may not coincide with that date. Rule of thumb: there is no such thing as an "all original" M1 Garand, unless you have paperwork and provenance showing the rifle was shipped from the factory, and where it has sat untouched since. A very rare item, as most known are in museums. An excellent book for researching "collector" Garands is, A Guide For The Collector, by Scott Duff, which breaks down, by manufacture and year, what parts are "correct". It can be used to determine only if the parts are "correct", or what you would need to make it so. I have put together "correct" ones several times, but always with the understanding that it's NOT 'Original"; others have not, and scams have been tried. Since, for over forty years, I have dealt primarily with competition firearms, and not "Collector" ones, I'm not fully versed in all the intricacies of collecting. However, sometimes even those who are are bested, so be careful. All things being equal, assuming the barrel isn't shot out, $800 is certainly a fair price for a good Garand. www.charliemaloney.com