As stated, that’s a 73-80 frame based on the frame horns.
All of the square body front springs are the same. The only difference will be the rear spring length (52” or 56”) and the ubolt hardware based on what axle you have.
Check your rear spring length, identify what axles you have and use that info to order the kit. For example;
If you have 52” rear springs and a 10 bolt rear axle, order a kit for a ‘78 K10.
The hole in the crossmember isn’t relevant to a lift kit.