Infoseeker, welcome to Quilting Board. Two good threads about 15 clones can be found at
Will the Real 15 clone please stand up and
Can you please explain "Clones?" These machines were produced after WWII in Japan. A lot of the 15 clones have a drop feed on the bed next to the spool pins. Some do not, like yours.
Does your machine have a JA or JC number somewhere on the base. There are a lot of 15 clones that do not have a JA or JC number. Sometimes the only way that one knows they were made in Japan is that it says so on the machine somewhere. I have one that it was hidden, on back of the pillar, by the motor. I believe there were some lawsuits over that. I can't find a good picture of a JC number but here are a couple of JA numbers.
Janey - Neat people never make the exciting discoveries I do.