So the steel beams were a feature of many but not all Lapworth designed Cals. They may or may not be present on the later models designe by others but I'm not really sure.
The beams seem to all be buried in the transverse hump in the
cabin pan. To tell if you have on look along the top of the
pump to see if any metal tabs stick up out of the hump and are thru bolted to the transverse bulkhead that sits on the hump.
The beams are generally a good idea because they do a WONDERFUL job of resolving
shroud forces into the
hull without adverse flexing you can see on other boats.
Because of the proportionately much high cost of stainless in the 1960s & '70s I assume that is why they were originally built using mild steel. Problems arise if previous owners have not kept the boat dry enough especially in a saltwater
environment. If you determine the boat you are interested in has a steel beam then it should be investigated for
corrosion. If nothing else you can buy your own Milwauki borescope at Home Depot for about $200.
I have a friend with a Cal40 and a PO installed screw-in
inspection ports to check the beam and keep tabs on it over time.
This page,
Wilkie's Sailboat Page, follows one owner replacing their beam.
Links on this page,
Cal Sailboats, show beams for several models of Cal.
I would not let the beam dissuade you from getting a Cal they are wonderful. I just bought a Cal20 and hope to have it in the
water shortly.
With the moniker Chinook92 I assume the OP is in the PNW. Is that correct?