Penalties for Obliterated Serial Numbers:
LA R.S. 40:1792 prohibits a person from intentionally receiving, possessing, carrying, concealing, buying, selling, transferring or transporting any firearm in which the serial number or individual identifying mark has been intentionally obliterated, altered, removed or concealed. Violation of this section may result in a fine of not more than one thousand dollars and imprisonment at hard labor for five years without the benefit of probation, parole or suspension of sentence.
Note that Louisiana law says
any gun and
intentional obilteration. This has nothing to do with the Gun Control Act of 1968. It also includes antiques if they had identifying marks. It's the intentional removal of an existing identifying mark that matters, nothing else. Guns in .38spl have serial numbers in the United States.
Another person, I believe, on this or the 1911 forum has contacted the ATF about a similar situation. Me? I think I'd just break down the weapon and dispose of the parts separately. If there are any originally unserialed parts, you might consider ebaying them.
Edited to add: Here is a link to the actual Louisiana law.
http://www.legis.state.la.us/lss_doc/lss_house/RS\40\Doc 97859.html
Note that antiques and war relics must be inoperable or not have readily available ammo in the U.S. If the antique gun had no identifying number to begin with, it is OK, but if it had one that was removed, it's not OK.
Here is a link to a case, State vs Buggs.
http://www-2.cs.cmu.edu/afs/cs.cmu.edu/user/wbardwel/public/nfalist/state_v_buggs.txt