Get the part # off the top of the sender... They only made that one for 2 years, 71-72. But the opening id the same as a 73 and they used a different fuel gauge with different resistance. I know this first hand since I lucked into a free NEW 73 sender and installed it only to find it was incompatible with my 72...
On the bright side, the 73 is a one-off sending unit and even more rare!
I found a sender from a 70 and removed the wire and rewound it on the 72's little wooden panel (inside where the wire is) and it has worked well for the last 3 years, but I still watch the trip meter to be safe... I'll always do that since I have only had one car that's fuel gauge really worked.
Good luck finding a replacement. Rainbow Auto in Bellingham WA had a new one a while back. I think he wanted $70 for it...
Alan

(2) 72' 145e's, 71' 144s, 67'122.... all still rolling.