No, you must drop the tank.
If there is an access panel, yes. You will find that there is no access panel and that you must remove the tank.
A torch
Remove access panel in trunk area--Wing nuts should release taillight assembly and bulbs twist out
Under the hood beside the battery.
in the glove box
Access through right side of trunk - remove panel and replace as complete unit
Go to the dealer with your ownership and have them make you a new key!
remove rear seat and insulation
Yes it is.
Remove rear seats
It should be in the glove box
If the 94 LeSabre trunk does not have a remote release, check the rear sear to see if the back is removable, to gain access to the trunk. If there is no access, then either a locksmith will need to pick the trunk or you will have to drill the trunk.