The non-Helecon can only be detected with a UV light, it doesn't show the orange helecon on the front and pink Helecon on the back, the normal 5d red does. The Edition N8 is quite obvious when viewed closely, they are both rare.
Normal 1965 Booklet Pane of 6 with helecon ink.
Stamp from the Edition N8 pane showing missing left shading lines.
The difference is:
Normal pane of 6 = $10
Edition G6 pane of 6 = $850
Edition N8 pane of 6 = $650
The values given are the current market prices.