F1 Chassis 086 at Artcurial

Not sure if this is the correct forum....

Chassis 086 (1985 Ferrari 156/85) will be auctioned by Artcurial on 7 February at their Retromobile, Paris auction:

Rétromobile 2014 & Solo Alfa by Artcurial Motorcars - Sale N° 2400 - Lot N° 340 | Artcurial | Briest - Poulain - F. Tajan

This chassis was raced in the 1985 season by Stefan Johansson in the Grand Prix of Europe at Brands Hatch and the South African Grand Prix at Kyalami. For the last race of the season (the Australian Grand Prix at Adelaide) it was the intended race car of Johansson, but he switched to the spare after the first untimed session. All of this is undisputed.

However, the Autocourse 1986 F1 annual (usually well informed) notes the following in their chassis log for the 1986 F1 season:

and lists this same chassis 086 as used by Johansson for the Detroit Grand Prix of 22 June 1986.

Now, if Autocourse is correct the chassis type as mentioned by Artcurial must be F1/86 instead of 156/85 and the 1986 Detroit Grand Prix can be added to the list of contested Grand Prix courtesy of Johansson.

If Autocourse is incorrect, what was the chassis raced by Johansson in Detroit?

 

To do some further research, I checked Cavallino magazine and found the following info in issues 33 and 34:

Brazilian GP 23.03.1986
Chassis 086 (still in 156/85 form) brought as spare, but used by Alboreto for qualifying. Cavallino magazine also thought him to use 086 in the race, but this was not 100% certain.

Spanish GP 13.04.1986
Again 086 brought as a spare. Confusion if Alboreto raced chassis 089 (type F1/86) or 086.

After this race, 086 is no longer used. For the Detroit GP of 22.06.1986, chassis listed are 092 (Alboreto), 089 (Johansson) and 090 (spare).

This confirms that 086 always was a type 156/85 and adds two 1986 races (Brasil and Spain) where it was used at least as a spare (and perhaps raced by Alboreto).