Are M105a2 top bows always wood?

The bows on my M105A2 have steel uprights and corners with wood cross pieces. Two of them are good, one is severely warped and the other two are rotted really bad. Were these cross pieces always made of wood? If later ones were steel or fiberglass, I'd like to get a set. If they're all wood, looks like I'll have to make some replacements. Just curious as to what is available and what my options are.

The later ones are all metal. And much better than the wood ones, unless you need the wood for period correctness.

And the metal ones will also fit the M101. Wayne

Thanks for the info guys, much appreciated! A fellow SS member here offered me a set at a good price so I'm going to upgrade to steel.