Your help with musket ball (?) finds.

Detected a local park today. Some of the park was once part of an 1846-'55 military post in the Highland Lakes area of central Texas. Didn't put my coil on much but did find a number of modern spent bullets...22, 25(?) and 284 caliber rounds based on grain wts plus a couple of shotgun brass. The surprize finds were two solid lead rounds, one of wich is nearly symetrical (round) while the other is partly round but disfigured from an apparent impact. They were detected approx. 100-150 yds apart and both rounds weigh exactly 410 grains. Internet search indicates these are/may be 50 cal. round balls. No pics, but both are white in appearance which may indicate age??? Neither was particulary deep...~ 5 inches, but one was recovered from under a moderately large (3" dia) tree root.

Question - is there any way to ascertain whether these are nineteenth century or modern smooth bore rounds?

All replies welcome and my thanks in advance. HH to all!

PS - Best est of dia. = 17mm