starsfan,
BC52 speaks the truth. While a factory engine would have #1 located in a specific tower of the cap, it can actually be anywhere you want....as long as the rotor is under that tower on TDC.
If a person were to bring #1 to TDC and stuff the distributor in however it fit, the location of #1 would be pot luck, and perfectly acceptable. The location isn't an arbitrary thing, only the firing order from that location. Does this make sense!
Stuart