If we like the look of the plain stucco finish, we can just leave it that or do we have to seal it with veneer or paint?

[FAQ]

If you like the look of the stucco - simply seal it every 3 years with an Organic Masonry Sealer. Make sure the oven is super clean an free of smoke / soot as you would be sealing those in.

Here’s a great sealer -

http://store.brickwoodovens.com/eco-advance-organic-masonry-sealer/