The original paint used on an SMLE is Suncorite, which is a very durable paint with high wetting capability, applied with a brush. Once dried, it's nearly impervious to solvent. Hit it with acetone, xylene, and it laughs at it. You have to go medieval with carbon tetrachloride before it'll come off (if you can even find any carbon tet).
But it does chip. It's not unusual for someone to get an SMLE with a chipped and worn Suncorite paint job and hit it with a rattle can. Later, someone else gets it, and it thinks it's all original finish. It's probably not. If I get a painted Enfield, I wet a rag with carb or brake cleaner (non-chlorinated) and wipe it. If the black comes off, it's not Suncorite. Usually I'll end up removing a fair amount of the Krylon crap, leaving behind an authentic, but chipped, original finish.
Suncorite is not available in the USA (thank you EPA), but I have heard of industrious individuals taking vacations in Australia that have been able to bring back small paint cans of the stuff. So, if you search around on other gunboards you'll be able to find someone that can sell you an ounce or two, which is all you need to touch up a rifle (if you even want to do that).
My recommendation, as a collector, is get rid of any Krylon rattle-can crap, and leave it as it was.