Plastic Lids On 1-18s
Frigidaire used these on a number of different lower priced models, I would assume that this was done to save money, I saw a lot of these over the years.
As Phil mentioned all the 24" laundry centers had plastic washer lids and dryer doors, these were changed to metal after WCI bought Frigidaire from GM and WCI was making a deal with GE to build the LCs badged with the GE name. GE insisted on this change for liability reasons because many FD LCs had gone up in flames and the plastic doors and lids increased the chances of the fire spreading to the rest of the house.
The entire heating element assembly was also redesigned and encased in a steel box on the LC dryers because of the very dangerous cheap design the the GM built LCs used. All you had to do was put something like a blanket or pillows on top of the dryer and if it blocked the vents at the rear top of the dryer you could have real problems.