Are you missing it all together, or is it just in need of repair?
When I was having my gauges restored by Palo Alto Speedometer, the question came up regarding calibration of the fuel gauge.
In my case I was able to repair my sending unit and do my own calibration but he did mention that they have some options available. I believe one of those involved using a newer style sending unit, but you'd have to get details from them if you want to go that route. Somewhere in the past, my float had been altered. I believe the original floats were cork, but mine is now plastic. I'm not too concerned about items like that which are not visible at all and increase reliability.