Most A3 receivers are pretty tough and it is probably fine--excessive headspace can be taken care of with a new barrel and probably worth getting a new bolt body as well. However, if you are worried about it, and the seller allows, see if you can use an led borelight and a small angled mirror to observe the locking lugs. If you have a good sense of touch, you can do with your hands, what you do not want is lug setback which can happen (unlikely but possible)--you will feel it as a slight depression in the locking lugs or something like burrs, grooves, etc. While A3 receivers are pretty hard all the way through and not case hardened like the older models, it might require a more expensive fix than you might be willing to spend depending on the degree needed to smooth it out. As hps said it, the safety lug should not be touching. However, at $299, you are basically purchasing an action and a sporter stock. From what I've seen on action auctions on Gunbroker, A3 actions run from $200-400 depending on whether the receivers were tapped, rare variants, original finish condition, drill rifle restoration etc. Springfield sporter stocks have to be pretty nicely figured wood to bring very much.
A lot depends on whether you want it as a sporter or to restore it to military configuration. Criterion makes a 1903/a3 short chambered military configuration barrel for about $200. Sarco in Firearms News/Shotgun News keeps advertising them for a bit less. There are some WWII era barrels in brand new condition that range about $200-250. The rest of the parts for a military restore are available right now.
Sporters, you will probably have to use a military barrel which may be aesthetically ugly (typically parkerized, little or no polishing, etc.) or have a gunsmith use a barrel blank/military type and create a custom barrel. Springfields, like Enfields, have a coned breech, square threads, and cuts for the extractor which is a bit extra work for a gunsmith compared with a Mauser barrel and priced as such.