Thank you tigre and Ironmachine for posting those photos of H. Kroeck's Bf-109E. The use of a white top hat on his plane supports the possibility that perhaps more than one dark painted Bf-109B carried a white 2.J/88 marking in Spain. But the available photo record indicates many J/88 Bf-109s were flown without staffel markings.
The following is in addition to my 7-14-2012 posting above. It is the result of a 'nuts and bolts' study of the J/88 Bf-109 photos available to me. It ignores the Bf-109V/A machines from the first batch of Bf-109s sent to Spain. All of these were delivered in a very light color top side finish, providing a high contrast to their black top hat markings. Only Bf-109A matricule 6o3 is known to have been later repainted in a dark greens camouflage finish, while serving with 1.J/88.
I have seen photos of only 15 Jumo powered Bf-109B/C/D variants marked with the 2.J/88 top hat staffel insignia. Those matricules are 6o19, o23, o29, o32, o35, o45, o47, o52, o53, o56, o60, o61, o64, o73 and that o2? with white top hat. All but the last, with the partially known matricule, show the top hat in black on planes that had been repainted in light gray camouflage on their upper surfaces. The plane with white top hat was photographed while still in its factory applied two dark greens camouflage finish. In every instance there is a high contrast between the camouflage and staffel marking.
I hope there are more photos of other dark green painted Bf-109s of 2.J/88, also carrying a white top hat insignia. It seems reasonable to suggest a white top hat marking was used on 2.J/88 planes still wearing their original camouflage, until they were repainted. Given the range of the matricules listed above, it seems unlikely all were in Spain and available to 2.J/88 at the same time. By the time J/88 was based at La Senia only four of the original Bf-109V/As are known to have remained in service. These were matricules 6o6, 6o7, 6o10 and 6o16. So how were some eight to twelve Bf-109s assigned to 2.J/88 marked?
The photographic record of J/88 Bf-109s remains incomplete, but it seems to indicate only one carried that white top hat marking. It would appear from the available photos the top hat marking was not much used by the original batch of Bf-109Bs to arrive in Spain, not until after most had been repainted in light gray, after some considerable time in service. This seems unlikely due to the apparent popularity of the top hat insignia with the pilots. Perhaps the situation was that not all 2.J/88 planes carried a top hat insignia for a considerable period of time or perhaps ever. There are photos of Bf-109Bs with matricules 6o17, o18, o19, o21, o22, o24, o25, o26, o27, o28 and o30; all still in their original dark greens camouflage, and none showing a staffel marking. Matricules 6o59, o72, o74, o80, o83, o84 and o95 were all Bf-109C/D variants, all with light gray top side camouflage and none photographed with a staffel or personal marking.
Finally and for completeness, I have not seen photos of 6o39, o65, o77, o81, o85, either one or the other of o41 or o46, or of o43 while it was still intact. The one photo of o48 is not from an angle advantageous to determine if it carried a top hat. Other matricules between 6o20 and o86, that were not cited in the above, are known to have been assigned to 1. or 3.J/88. There are enough gaps in the available photo record (if and when filled in) that could change the direction of the observations given above, if only we had those as yet 'missing' photos!