no coin to show. Hypothetical question. Assume the coins looks good for its grade and year. My question is around what coin retains its value better and has better future upside for future generation to inherit. Would you buy a scarce date with a MS63 or a common date MS65 if the price is the same?
Without having more information for this hypothetical I would go for the scare date especially if the common date is common in 65 as well. Generally speaking common things will remain common.
A common date can be more difficult to find in different grades. What is a common date in AU-58 will usually become harder to find in higher grades. Look at any coin graded by PCGS or NGC and you'll see what I mean. MS-64 is common but in MS-63 or MS-64 the same date and mintmark are more difficult to get. I've been searching for 3 years for 3 Peace Dollars graded by PCGS in MS-64 and 2 dealers are looking for me. Still can't find it. It's a tough grade to find but they are fairly common in lower grades. One day I'll get them. I would tend to buy the scarcer date over a higher grade. Scarce is always scarce.
The scarcer date will at least also include the subset of people who are collecting them for numismatic reasons, where the common one won't.
A common date PCGS 65 is selling for approx $1750 or you can buy one of the following better date in 63 for approx the same money based on CDN prices.... 08-P WM, 13-D, 15-P and 20-P