Front brake wise it looks like it is still on the original bore sized master cylinder (5/8") Be aware that the front brake is not really up to the road conditions/traffic we have now. If you have yet to try the brake in earnest do so carefully. To improve the front brake there are various kits/upgrades available. From replacement discs, calipers, master cylinders, double disc set ups etc etc. The most cost effective i.e. biggest improvement for the least money has to be the sleeve kit from RGM
£49 +vat and get it fitted. That and a pair of pads from AN transform the front brake and it is almost invisible so not altering the 'standard' look.
Adding to L.A.B.s list
Should have fork gaiters
" " " Mud guard flaps
Cloth covered wiring harness, should be pvc tape wrapped.
All of this info is what we have gleaned from the photos, the 64,000 dollar question is what are the engine, gearbox, primary drive internals like?
Get hold of a decent i.e. long and strong, exhaust ring tightening tool and really make sure they are tight and prevented from undoing (the forked washers that are bent to engage with the rings and fins are shite) the better way is to lockwire the rings to each other with a tension spring so the spring live loads the lockwiring . Failure to observe this and the rings coming loose will ruin the thread in the cylinder head = much expense in getting that repaired.