Yes, it is an issue with design of the old filler style and new gas pump nozzles. If you have ever seen an old, leaded fuel dispenser, the tube diameter is significantly larger, and most were relatively less curved. In fact, when unleaded came into being, the nozzles and the filler neck openings were specifically made smaller, so folks wouldn't put leaded gas into a car that required unleaded.
67-68 are hard to fill with a modern filler, particularly those with the vapor recovery system that requires the collar to be pushed back before the pump will send fuel. 69's have an issue because, although the filler is behind the plate, it has a little less curve and is easy to overfill too.
The best way I can explain to someone who is not used to fueling an older car like ours is to bend over and listen to the change in tone as the tank becomes close to full, and then really throttle back on the trigger. Once you have done it a few times, you will know what I am talking about. When I used to fill either my 67 in HS (mid-1980s) or my 68, I had an old towel in the trunk to put under the filler opening to catch any drips. If the station has a window wash station, the blue paper towels work nicely for that too.
Either way, you have to pay attention when filling our old cars. Locking the trigger and letting the fuel fly is a recipe for around a quart of overfill on the tail panel, bumper, and ground