Ha: it turns out there may be something missing from the kit - but not something I need, happily! A slip of paper in the box with the instructions tells us, in German:
Dieser Packung liegt ein Spezial-Klebstoff (Plastikschlauch mit blauer Flüssigkeit) bei, der nur fur die Verbindung der Kunststoff-Radsterne mit den Messing-Radreifen geeignet ist. Jeweils einen kleinen Tropfen in den Radreifen geben, dann den Radstern eindrucken. Die Radreifen anschliessend ausrichten und uberprufen, dass sie keinen Seitenschlag aufweisen. Der Klebstoff bindet innerhalb 24 Stunden ab. Uberschussiger Kelbstoff kann hinterher abgerwaschen werden. Fur die ubrigen Teile ist dieser Klebstoff nicht verwendbar!
I include this for the benefit of anyone reading this who wants some practice in translating reasonably technical German... For everyone else (including me) Google Translate makes things clearer:
A special adhesive (plastic hose with blue liquid) is included in this package, which is only suitable for connecting the plastic wheel spiders to the brass wheel tyres. Put a small drop in each wheel tire, then press in the wheel center. Then align the wheel tires and check that they do not show any lateral runout. The adhesive sets within 24 hours. Excess adhesive can be washed off afterwards. This adhesive cannot be used for the other parts!
There is a small plastic tube (apparently rendered as 'hose' by the translation) included in the kit - you can see it in the second to last photo of my previous post, peeping out from beneath some other parts, in the compartment towards the lower right-hand corner, above the one with the wheels. The contents aren't blue though, they're a sort of brown colour and I thought it was a tube of oil, as mentioned in my last post. I'll be using other wheels anyway, but I'll cut open the tube, carefully, with good ventilation, over a suitable receptacle, just out of curiosity to see whether it is glue or not and possibly find out what type it is - Edited: I was unobservant - the back of the instructions refer to 'loctite glue'...
The tyres are turned brass as far as I can tell and the axle and centres assembly is plastic, so I'm intrigued as to what adhesive they provided in the 1980s that was thought suitable for a good long-term bond between those two materials. Come to that, I wonder why they didn't just provide ready-made wheels, which I thought was the norm even then. Am I wrong about that - did kits in those days often provide unassembled wheels?