Hmmm....   I thought I had replied to this last night, but I don't see it here today...

Like Graham's s/n 107133, my s/n 107129 also has the large holes in the front.  Perhaps one day midway through production of the unstyled Pacemaker, someone discovered a pile of 12-20 front plates and decided to insert those into the Pacemaker production line..

By the way, those "large holes" are the mounting holes for the Challenger front end assembly, correct?  The Pacemaker and Challenger did share the same u-frame components, didn't they?

Maybe this can lead to a Pacemaker serial number registry??

Cheers,

  JB