These bullion SAS wings are found on both a red background for Full Dress and on navy blue for No.1 Dress. They can be found with silver wings and gold parachute and gold wings with silver parachute, the former said to be for Other Ranks and the latter for officers. However, like many things in the British Army, it is difficult to find where this distinction is said to come from and it is easy to find exceptions to every rule, such as the CGS wearing what should be ORs wings on his No.1 Dress (but as the CGS he can do what he likes....
) often each regiment will devise its own rules, regardless of what the Army Dress Council might have decreed, and equally tailors might use whichever version of the wings they have acquired, especially for rare badges such as bullion SAS wings where few know of any regulations.
Just to furher muddy the waters I attach a photo of a Guards general wearing the gold wing version of the SAS wings on his No.1 Dress in 2016.....