Guys,
"D3Sx" indicates that this is "intended first application" as 1973 Thunderbird (S). For the snorkel only. The entire "assembly" would have yet a different part number assigned to it.
It is facing the right direction for a regular car. Note the tin formations in the center hole where the front casting of the carb would orient it properly. Pantera would or could have the snorkle at the 11:00 position using the same picture as reference. Depends on the year......
This style, with the "auxiliary air inlet" on the RH side in the pic (driver side when installed) was used on 71-73 GT/CJ 351C's even perhaps Boss if not ram air. There could be d teeny tiny date stamped into the aux air unit somewhere.....
The bowl could have a date stamped into it....and maybe not......kinda touch and go with that style of bowl as it fit a BAZILLION different cars and trucks.......and got a hole punched in the side for the aux AIR inlet when needed.
CJ's and GT's could get either a chrome or a painted lid.......usually chrome.
SO, the most that the stamped numbers can tell you, as indicated, is that this was from something mid to late 1972 and upwards.
Later Panteras had all sorts of crazy snorkel locations plus other pieces that may have picked air up from lower towards the chassis, and then there were shields that appeared around the aux air inlet to perhaps give "more calm" air into the air cleaner??? But the early 71-72 Panteras seemed to have just plain ol' car air cleaners to my knowledge......but I don't know everything...... yet....! 
Steve