The Bf 109E of the Condor Legion coded 6 • 88 was a Bf 109E-1. Sadly, I do not know the Werknummer, though a Bf 109 expert might be able to at least say who the manufacturer was (Arado? - the bird must have been a very early E-1). Here's some other information on the machine:
Mombeek ascribes 6 • 88 to Oblt. Siebel Reentz. Photo in Mombeek reveals at least one white victory bar on the fin. Remains of this aircraft recovered and taken to UK for restoration in 1987.
Cerdá, Les Mess. espanols, pp. 26, 41, 43, photos; Cerdá, Los Cazadores de la Leg. Con., p. 89, photo; Mombeek, Lw. Colours, I, Sect. 2: The Spanish Civil War, p. 172, photos.
RA