Neither would I, if it was from around the 4th or 5th Century.
Constantine I was a sun worshipper, who continued to
mint huge numbers of coins declaring
his relationship to
Sol Invictus long after
his supposed 'conversion'. He issued two rescripts regarding, not Sunday observance, but abstaining from
work on 'the venerable day of the Sun'. In the following century, Leo the Great complained about people doing their devotions to the sun on the
Vatican steps, on their way in to Mass. It's no coincidence that we've ended up celebrating Jesus' birth on Dies Natalis Invictus! Such a connection from the 1st Century, however, would surprise me a great deal.