Repairing Fuel Sending Unit (question)

[Redshirt]

I just pulled my fuel sensor/sending unit off to turn it around (shop put it on backwards). As I have with everything Ive touched, I figured Id give it a quick brush off to clean it and... snap... I broke the small wire from the plate side (inside-facing thin wire from sensor to disk riser on base of plate).
Is it okay to solder it back on?
Also, should there be a gasket covering that portion (where the soldered piece is down to the plate)? It will be inside the tank and I dont know if it originally had one.
The sensor and its riser are fine, just the wire at the base of the plate has the wire popped off.