L3 ~ L5 ~ L7 were from the early 90's IIRC,so almost certainly not those if these were bought in the early 80's.
IIRC the L26 & L100 were available to the mid 70's and the L65 were available to '79,obviously some models from that late 70's era carried over into the early 80's,but I dont think any of these did,though I freely admit that I could easily be wrong. Pretty sure a few I mentioned above were like that (carry-overs from the late 70's).
Again a big part of this depends on whether these were bought new -or- used. And no doubt some of those 70's models did'nt always sell right away either,so a few of them could've lingered on the shelves for quite some time. And of course there were others models as well,but many of those would be considered bookshelf speakers or studio monitors and not necessarily "true" floorstanders.
There's a price list over @ the Lansing heritage site that has dates for when certain models were available,so the OP can look that up for more specific dates/models.
Without more info it's just a good old fashioned guessing game,,,all we can do is work with the clues given thus far...
Good luck to the OP,it sure will be interesting to find out what they actually are.
Bret P.
