I've made that mistake before... it's just like doing a tune up, and mistakenly pulling all the wires at once instead of doing them one at a time. You're like :doh:

In the machining process of most engines, the caps are cut from the cast, bolted on to the block, and bored out afterwards. The sides of these parts usually have some tool marks from the milling process. It's harder to see them with the crank and rods in place... See if you can line any of those up.

It works on a DSM, anyway... and I think my ol' D series had the milling marks on the sides of the caps, too... but I had all of those lined up in a magnetic pan when I rebuilt my last 4 motors, and wasn't really looking closely at them.

I'm sure others would be curious to know if there are any distinguishing marks of any kind as the plastic baggie method is the most common one used, and doesn't work when it comes to main and rod caps. Those should always be bolted right back on to the engine in-order after removing each rod, or the crank and bearings.