Time to update this from experience in gaming,buying,& selling. Nintendo 5 screw carts are the original carts ever made by Nintendo. During the 1985-1987 era & 1st manufactured games made. Now it like any collector take books do you want the 1st edition or the reproduction.
Now there are ways to identify a true 5 screw cart. If someone hasn't tampered with it over the years.

People do switch backs on carts and I have even seen 3 whole back carts have screws in them instead of the 3.8mm screw.
1ST- Nintendo original series games the carts will have on the back label no copyright symbol & Nintendo will be on the far right hand side of the label.

2ND- All screws in cart will have a little circle & you will need a small flat head screw driver to get out any of the screws. If you need a Phillips head screw driver the back has been replace also there will be 5 braces inside the cart for the screws. Where there is only 3 now that is another why to tell original to hold the cart chip in place

3RD- not only did Nintendo make but also games in that time frame there are Taito , Data East, Bandai, & others but have to be before 1988.Those do have a copyright symbol though swith Nintendo in the middle

Well I wanted to update this a little more so more people were aware to look for since 1st writing my guide originally I saw more sellers using it.
Not just as a seller but a gamer too wanted to give you things to look for if someone was scamming you
If it help some or anymore suggestions plus things I find I will add.
Hit yes for me if it did onemixer