Nope, not a WIDGEON...... and as a former WIDGEON owner, I can be sure of that! However, I am fortunate to have had a couple of neighbors who owned what is called a "TECH DINGHY". What youy have is just that, a TECH, also known as an MIT TECH Dinghy since that was where the design originated. Built by several companies over the years, yours appears to be one of the ones made by BEETLE BOATS (New Bedford, MA) or American Boatbuilding Corp. (New Bedford, MA and Warwick, RI) in the 1950s and early 1960s. Do not confuse BEETLE BOATs with BEETLE CAT, same family, but different company (Father built wooden cats, son started company building fiberglass boats). American Boatbuilding was more or less the merged company formed between BEETLE and Marscot Plastics.
The boom shown in the picture is not for the TECH, the TECH has a loose-footed main, 72 sqft in area. The boat was cat-rigged (marconi or jib-headed sail), although there was an option of a sloop rig for a while. Several of the Beetle fiberglass boats used a centerboard lever very similar to the O'DAY centerboard lever, perhaps the original one on this boat broke or was lost and the replacement was bought from an O'DAY dealer? One other possibility, and that is due to the fact that Marscot Plastics built the O'DAYs from 1957-61 or so, perhaps they grabbed the "wrong" CB lever. <GRIN!>
I don't recognize your lake, so I don't know how far from Massachuestts you would be, but ZEPHYR Spars in Wareham, MA was, to the best of my knowledge, the supplier of masts and booms to BEETLE and Marscot and they should stil lhave the specs. I'd offer to measure the mast of one of my neighbors' boats.... but they've both sold their TECHs many years ago. Another neighbor has a newer (I think?) model of TECH, I might be able to measure his mast. The size of the extrusion should be the same as for a WIDGEON, but I think the TECH mast is a little shorter, though I doubt very much shorter. If not trying for absolute accuracy of rigging, I might buy a WIDGEON mast and mainsail (unless you have the TECH sail?). You will need to modify the standing rigging of the WIDGEON to match the TECH, but it would be a start! Widgeon mast is 18'6" and boom is 8'6".
I've attached a few pictures that may help. The drawing of the sailplan is a newer version than yours, and it appears the mast is a little taller and the boom a bit shorter than the ones of the vintage of yours, but you could still use that for an example. I have more, but many of them are of the sloop-rigged TECH, which may still help since the mast. boom, mainsail, and position of the mast were all the same for both versions. The centerboard trunk was moved forward to keep the proper balance in the rig. I just noticed that the pics of the TECH with the tan deck are of a sloop-rigged model, you will note that the CB trunk is further forward. However, it is still a good reference to the mast and boom proportions.