I have a D-25 (archtop rear with I think a mahogany body and top) with a serial number (on the headstock and the sticker in the body) that reads 1l0121. The second character is somewhat nebulous. If it is the number one, per the Guild dating PDF that puts the manufacturing date as 1974. That sounds about right as I purchased it in 74 or 75. I did a lot of research on this forum and could not find a definitive answer as to what the second character should be. One person suggested a lower case L, but got a reply that it was an uppercase I. Neither of those letter possibilities works in the serial number PDF. Could it be a separator? Any guidance would be helpful. Thanks.