The LRC is a simple resistor network. 

I've measured the resistance in ohm with 
the various buttons pressed, and came up with the following:

Nothing pressed: 1407 ohm

auto loop: 128 ohm
rehearse: 77 ohm
locate 0: 280 ohm

set locate: 435 ohm

loop start: 229 ohm
loop end: 180 ohm
punch in:330 ohm
punch out: 381 ohm

rewind: 1107 ohm
f.fwd: 1207 ohm
stop: 1009 ohm
play 897 ohm
rec 1305 ohm

rec+play at the same time: 800 ohm

set locate+any button with lower value 
gives the resistance value of the button with the lower value

When ordered, a pattern emerges. The main buttons seem around 100 ohms apart:

Nothing pressed: 1407 ohm		~1400
rec 1305 ohm				~1300
f.fwd: 1207 ohm 			~1200
rewind: 1107 ohm			~1100
stop: 1009 ohm				~1000
play 897 ohm				~ 900
rec+play at the same time: 800 ohm	~ 800

The other buttons seem around 50 ohms apart:

set locate: 435 ohm			~ 430
punch out: 381 ohm			~ 380
punch in:330 ohm			~ 330
locate 0: 280 ohm			~ 280
loop start: 229 ohm			~ 230
loop end: 180 ohm			~ 180
auto loop: 128 ohm			~ 130
rehearse: 77 ohm			~  80

These values match between old and new LRCs. 
Enjoy!