Its hardly a big deal. Your original bolts should have had 2 for #1 & #2 bolt holes. If you are bothered about it you can wind some metal adhesive tape round two bolts near the head to make a dowel effect to position the head and remove them (replaced with 10.9 or greater strength bolts after the head has had all the other bolts fitted and nipped by hand). Then I do 3 stages of torquing to 24ft lb. 10, 18, 24. If the gasket is the grey graphite type - assemble dry. Others will have other opinions!
Thanks, my original bolts didn't have any dowel bolts and there weren't any in the replacement set I got. As people seem to have said it is important to use them I thought I should - I'll try the tape if I don't find any.