gummi, this is 900 miles from me.
but, i am going to disagree with you about it being a weber lid. It is almost certainly a Sears Economy lid (made by weber of course). Look at the handles. This wood shape was used independantly on both sears and HC models, and the handle shape matches the bowl shape, so either it is a HC or a Sears, but the parts are consistent, and they are not the weber shape.
I believe, in person, you would see that the top lid vent has no writing on it except a single stamp of a date code (L through EO probably). The economy grills were just like weber vents, without the weber logo. They were attached via bolts, not rivets. The bottom vents on these sears grills are identical to their weber brothers excepot they too are attached by bolts. They are not the 'double notched handle' vents from a happy cooker. Unfortunately, we can not see the vents on this bowl. So I am guessing here.
now, one wildcard, i was not unconvinced that Unarco did not also supply whoever assembled the sears cookers with some parts (like the wood handles and the freaking ash pan*1 we are talking about.....) at some point during their life, but I was never sure on that. Note: What is left of the wheels on this one look like the remnants of happy cooker white wheels, not the 'black weber' wheels that I am familiar with seeing on the Sears grills.
sooooooo, if Ida wants to send this person an email to ask about the bottom vents, I am sure he could convince them to mail them for the right price..... It is very possible they are the notched HC vents, but if I were forced to guess, this is a sears economy grill both top and bottom, and he will find standard weber vents with a date stamp on the bottom.
*1 Isn't it strange that these ash pans appear in both weber built Sears grills as well as earlier Happy Cookers, which we have come to learn were made entirely independant of weber. Do you recall in our tale that Weber BOUGHT TOOLING from unarco? I think this is the specific tooling weber used from Unarco.........