They often painted British rifles used in the Tropics. The paint is called Seconite and is still to be found for refubishing purposes.
Its also possible that a more modern Baking laquer or Alumahyde finish has been applied to hide defects.

Reproduction stocks which are manufactured from No.4 stocks are sometimes available, as are the metal parts and repro buttpads, the buttpads are usually hollow and better at absorbing recoil than the originals, which seem to have been intended to protect the buttstock from cracks after being bounced on the ground rather than protecting the shooters shoulder.

$349 sounds a bit high to me. You'd have about half again what its worth in it by the time you bought everything you'd need to put it back in its original appearance, and most if not all the parts you'd have to get would be repros rather than original equipment.

If you ran across a No.5 junker with good wood and switched out the stocks you might trade off the sporter stock and parcel the junker out or save it for spare parts.
Still the quoted price is too high, for me anyway, and I wouldn't mind having a sporter stocked No.5.

PS
There are Military issue Sporter stocked No.5 carbines which were issued as aircrew survival rifles, and to police for animal control in Canada.
If I can find a page with images of those I'll post a link here. They are worth a lot more than a No.5 in military trim.
EDIT
Looks like the EAL rifle used a highly modified and lightened No.4 action rather than the No.5 as I'd thought. Its worth a look in case an EAL military or civilian variant stock found its way here and ended up on this No.5 action.
http://enfieldrifles.profusehost.net/ri14.htm

One rifle I'd dearly love to have, and missed out on buying in mint condition because I was too young at the time, Is the Canadian made Light rifle. It used a no.5 action modified for use in a one piece stock made from some sort of chip board. The barrels were 23 inches or so with a very slim profile. The rifles weighed less than a No.5 and had a sporter type ventilated recoil pad.
The composite wood didn't hold up well in tropical wet weather, and it kicked like Bruce Lee on crack.
The remaining test batch were parceled out to Canadian Constables for use in case a Grizzly decided to stroll through the neighborhood. Not a bad idea since our own local police found that riot guns made no impression on the Bull Elephant "Old Diamond" when he broke out of the breeding facility here and rampaged through town.
Not sure if even a .303 could drop that bad boy unless AP ammo was available to reach the brain.
We get Black Bear around here on Occasion , one strolled through my back yard a few years back. He left in a hurry when I let the dog out. When the Deputies tranked him the next morning the Blackie weighed 160 pounds, a young adult they get to 350 or better with 600+ pounders on record. My dog weighs about 130, probably more since he just won't stick to his diet and I don't have the heart to let him go hungry. I'm a bit worried that someone will mistake him for a Black Bear one day.
I ramble on a bit at this time of night.