The only difference between a 69 and 70 hood to my knowledge is the inner structure has larger holes to accommodate the larger twist lock style hood locks on the 70 MACH 1.
I believe FORD only sold the 70 style as a service part after the 70 production began. I used to buy hoods 25 years ago from FORD and they had the D0ZZ part # which is for a 70 even if you ordered it as a 69. As for a outside appearance and dimension they are identical.
well there are more differences then you think.........
1) the front corners on the underside are slightly diff.........see pic
2)the area for hood pins as mentioned
3) next to the hood latch there was an indent on the bracing the hood latch bolts to.....seems there was a change maybe Jan 1970 on this?
I will post a pic when my other computer gets back from the shop if Jeff or someone does not post before
also hoods have a date code on drivers edge on underside