Craig
http://www.aerosekur.com/as_brochure...encyFloats.pdf
This document has some photos on pages 3 and 4 of a 109 Power with the floats packed away, and deployed.
You'd notice if they were on in the hangar they are not particularly subtle.
Held on by removable pins at front and rear of each float to brackets that stick out of the airframe, brackets that you really don't want to bang your head or knee on, they are pretty solid.
Accident Aircraft with floats installed, just for interest.
Gary