I need to know if there clips to hold the backrest in position, this is on a runabout 23.
Yes, clips of fabric, either webbing or reinforced top material. You tack the loop, and adjust the backrest spring to the proper height.
That height is to align the rear back rest to the rear rail, and to allow proper clearance of the seat cushion that slips under the backrest upholstery.
'27 touring rear seat, but loop strap method is the same for all open car back rest springs.