Your best course of action is to drop the pan and look.
I'd say yes, a rod decided it did not want to play nice anymore. Either that or some really big piece of something else decide to go dancing in the pan.
If it is the rod, 9 times out of 10 the engine lost oil pressure long enough to destroy the rod's ability to turn on the crank.
1981 Jeep CJ7 4.0 HO, AX-15, D300, D30, D44, SOA
1977 Chevrolet C/10 step side 454 TH400 3.73 posi