Your 123 cosmetically is in pretty good shape, the hood looks amazing for it's age, so does most of the paint on the machine!
The dash tower, particularly in the badly rusted area you highlighted, must be a common issue on these machines. Both my 106 and 107 have a single crack on the right side in that spot, and the 106 clearly has been welded on both sides of the tower, in that same area. My 147, which sat outside for 15 years, has a fair bit of rust there too.
The fenders appear original, it's that seat that's ruining the old-school looks! Supposed to have one of these on it:
Ignore the gear shifter the same seat was used on the 122 and 123
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'70 107 with k301 engine swap
'71 106 with 38" deck
'70 147
R with factory replacement k321, 42" deck
'61 Original with 38" timed deck
'63 70 "pinkie"
1863 with 54" deck
'46 Farmall H, '50 Farmall Cub
105 x2 (parts)