First, Tim., Welcome here!!!!
2nd, the leg setup looks different than any we've seen before.....very different.....
See here these two 47cm kettles, very new & very old, from another post:
http://weberkettleclub.com/forums/weber-kettles-accessories/mount-prospect-il/msg116372/#msg116372It appears the front leg on your Brownie is a back leg, inverted, with an additional fitting of some type to stabilize it........the back legs, I've never seen anything like the curved structure near the wheels......very unique.......
It may have been the original owner fixed this up somehow, as a re-fit from the standard Weber set........or, a very rare Weber prototype of some kind.......................stranger things have been seen from Weber, as they developed styles in the past.......
at any rate, very extra nice kettle........a nice surprise to see that they are hiding in barns & garages all over the world & congratulations for rescuing a piece of history !!!!!!