Unlocking content controls (if locked) is only necessary when deleting them, not when adding rows. Unlocking & relocking may just be a coding-style thing, but it's quite unnecessary when adding rows.
For adding rows with content controls to a table, take a look at:
https://www.msofficeforums.com/word-...tml#post119230
https://www.msofficeforums.com/word-...ire-table.html
For adding entire tables with content controls, take a look at:
https://www.msofficeforums.com/word-...tml#post118315
None of these messes with the content control locked state.
For content control deletions, take a look at:
https://www.msofficeforums.com/word-...tml#post118924
Even then, unlocking them is unnecessary if they're not already locked, as the subsequent posts seem to suggest was the case (the .LockContentControl = False line was omitted by the OP).