Great, John. Thanks. My covers fit with the two week requirement (if you read the bottom one as "MAR [4]" and figure that the date had not been advanced to the 5th). The backstamps on the one to Ogden, Utah cover shows a general delivery receipt on Feb 23, but then has a CDS on Mar 5th. Both of these have the sender's return address on the back. Could these have been returned to the sender through the mail? I have a third cover, same sender, sent to North Platte, Utah:

This one clearly looks like it was returned via mail to the sender, sent back on Feb 21, despite the "MAR 3 -- 1934" marking.