I don’t know what this may have originally been attached to, but I don’t think it has anything to do with Welsh heritage.
The traditional Welsh Red Dragon (y Ddraig Goch) has an arrow-shaped tip to the tail, whereas the tail on this one has a tufted end. That’s consistent with it being a griffin, which has the body of a lion, whereas the dragon has a reptilian body. Also, the wings are clearly feathered, which is again consistent with a griffin (having the front half of an eagle), whereas the Welsh dragon has leathery bat-like wings.
In general, heraldic dragons have a reptilian body with the tail either ending in a diamond or arrow-like tip (like the Welsh dragon) or tapering to a snake-like point. Heraldic griffins have a lion-like tail. The front half of the griffin is usually feathered and the forelegs eagle-like. Although both generally have talons, the griffin only has them on the forelegs, with the hind legs having paw-like feet. That’s what I see here. However, the head of the griffin should also be eagle-like and beaked, but here it’s not. Either of them may have a tongue of flame issuing from the mouth (as here), but the snout-like shape of the head is consistent with dragon.
It appears to me to be a hotch-potch of elements with the characteristics of both griffins and dragons, probably created as an artistic fantasy with no heraldic significance.
PS: there is a third heraldic mythical animal often confused with dragons and griffins: the Wyvern. These are also dragons with bat-like wings; a diamond, arrow, or snake-like tip to the tail; and a non-beaked mouth, but distinguished by having only two legs.
