This unit is in my attic in a horizontal position with the vent in the upper left hand corner as you look at the unit with the cover off. Does my blower motor and filter lie at the opposite end?

Probably,, although I`m not totally understanding what you are saying
Many times when furnace is in the attic,they will put the filter behind the return air vent so it can be changed without going into the attic

No they should be at same end... might not have a filter in there at all. Do you use filters in grills in the house?