Averaging the last 25 aircraft off the line, separated by 3x3 (15 planes) and standard (10 planes) It looks like there is an average difference of about 15 lbs.

Or, 51 lbs for 3x3 (averaged over 15 planes) and 36 (averaged over 10 planes).

This is with a variety of options so specific airplanes varied as much as 48-55 lbs for 3x3 and 32-38 for standard gear.

All of the above weights are for level flight as weighed. The tail-wheel weight would be more sitting on the ground in three point.