Posting a pick would make it easier for us. But I'll give it a go...
The No.1 Mk.III (&Mk.IV) had a "nose cap" that fit flush with the muzzle. On this cap there was a round protrusion below the barrel in which the bayonet ring fit around. The Mk. III was usually set up as a grenade launching platform, which is normally identified by a wire wrapped handgaurd.
The No.4 Mk.1 (most likely being that yours was manufactured in 1942), had the muzzle protruding from the stock. There is a handgaurd ring arond the stock ~ 1" from the end of the stock, and the front sight is tight to the stock. Just back from the muzzle, there will be 2 square protusions (one on each side of the barrle) that hold the bayonet.
Those are the most common Enfield rifles encountered today. The next being the No.2 and No.2A, these are most commonly found in 7.62x51 (.308 Win.). There is also the Pattern 14 Enfield, that really is an Enfield in name only. It is a Mauser action, built in the US by Remington, Eddystone (also a Rem. company), or Winchester. It is chambered for the .303 British cartridge. The "P17 Enfield", is wrongly (nick)named also. It is the US Model of 1917, chambered for the .30-06 cartridge. It is identical to the P14 in every way except for it's chambering.
That covers most of what I know on the subject,
Wyman
ETA-You can do as .351Win suggests. The model # is on the left side of the reciever, but if the gun has been rearseneled, it may be filled in with black paint.