steve, spedo's are not real hard to mess with.  providing that your 
numbers and needle are all ok, the rest is easy to do.  get up under your 
dash with a flat head screw driver and take the speedo out.  you will 
have to first detatch the acc. cable from the back.  just unscrew it.  
the dash lights pull out of the housings.  it may take a little prying 
because they have been in there for a while.  make sure you take notes on 
where they were to begin with.  after that, there are two screws that 
hold the spedo in.  they are on the left and right side of the speedo.  
when they are loose, rotate the speedo and it should drop out of the 
dash.  unbolting the parcel tray may make life a little easier.  take the 
speedo out.  with a fine screwdriver, pry off the chrome ring on the 
speedo.  take care not to dammage it.  it will pop off eventually.  undo 
the retaining nut on the back post of the speedo and the whole unit will 
come out of the housing.  now you can replace the colored strips with new 
ones.  be very carfull with the needle.  they are old and break real 
easy.  i have broken more then my share of clear early needles trying to 
extract them for restoration.  you can dig further into the speedo if you 
want, but you should not unless you find something else wrong.  i have 
rebuilt about 5 of them so far without trouble.  i make it a habbit of 
collecting extra speedo's for parts down the line.  you can pick them up 
cheaply at shows.  hope this helps.

take care and God Bless
matt