There's a few tabs / chords on here but I believe 
this one is the most accurate for solo guitar 
interpretation.

The verses are just G / Dm / C (all open)

the timing is slightly difficult to get right but 
listen to the recording to hear the changes.

Then the chorus is C / Bm / G / Em / D / Bm / C 
(all open except Bm).

So it goes...

G
Do they
C
know
Bm
those
G
days are
Em
golde...
D
..eee..
Bm
...eeen
C

C
Build a
Bm
rocket boys
G

etc etc etc,

Hope that gives you some idea of how it goes. In 
the verses, the Dm to C progression might change 
to something else at some point but I can't work 
out what exactly. Maintaining the Dm to C change 
doesn't stick out too badly (it may even be 
technically correct) and only a pedant would 
notice in a performance.

Any comments appreciated.