Heater core have pins or fasteners?

[Dibbons]

Re: 72 Ply Sat Sebring Plus (no A/C) I have removed the heater core to find it has a small hole in each corner of the heater core frame. There is also a larger blind hole (no threads) that correspond to these same holes in the plastic/fiberglass heater box. The holes line up perfectly but don't seem to have any purpose. Am I missing some locating pins or do you think the holes are for other years/applications? Thank you. Foto arrow shows the small hole in each corner of the heater core (hard to see)>

 

[rrTor-Red]

It's been a while for me but I seem to remember those holes line up between the case halves and a fastener goes through all three parts