96 - 98 Lance Squire with the All Weather option has a decal on the side of the rear entrance door frame that says "Foam Core". Also came with inside the window frame storm windows and thus has the plastic turn tabs on the black aluminum window frames or if your Lance was purchased used and the tabs are missing, the self tapping screw holes will still be there.
We had purchased 2 new Lance TC's in 1997 and both were ordered with the All Weather package and how we know. One was a 9-1/2' 1997 Lance Squire 4000 for our 2500 extended cab long box 4x4 truck and the All Weather package was an option. The other is a 11'4" 1997 Lance Legend 990 for our 3500 extended cab 4X4 dually we had at the time and the All Weather package was included as it was their top of the line model.
Still own and use this TC yet today on our diesel truck as it still in excellent condition as has a 3400 watt built in propane generator and 2 30# PP tanks and everything in the TC works. Excellent TC and have camped in the U.P. of Michigan in February with temps even well below zero at night when snowmobiling for 3 days. The extra insulation and the storm windows sure helped and so did the optional carpet package we'd ordered as the inside of the Lance 990 never got below 70 degrees even once and no water lines froze either.
Poured one gallon each of -35 degree windshield washer fluid in the black and gray water tanks and if any freeing were to occur, it would only turn to slush rather than freeze solid. It works! The fresh water tank is inside the TC at the front camper lower wall so it wouldn't freeze anyway as it has vents to the inside heated area and of course the water heater sure wouldn't freeze as it's hot!
BTW, I still original Lance brochure we'd selected which models and what options we wanted and had ordered from over 21 years ago! It has all the info/specs for all 96 - 98 Lance TC models.
A superb CC LB 4X4, GM HD Diesel, airbags, Rancho's, lots more
Lance Legend TC 11' 4", loaded including 3400 PP generator and my deluxe 2' X 7' rear porch
29 ft Carriage Carri-lite 5'er - a specially built gem
A like new '07 Sunline Solaris 26' TT