MontanaLarry

Hello group, I'm new. Thanks in advance for the help! I'm an amateur collector, lots of coins and books but not many with real numismatic value. In 1983 I purchased a sealed bag of 90% silver quarters, $500 face value. The cloth bag has "U.S. Bank" printed on it and what looks like a lead, crimped seal. The seal looks like it has white paint on it with 3 raised letters that are hard to make out. Looks like "NOC" or "NGC". The bank bag looked several years old when I bought it, perhaps from the 1970's. Many times I have been tempted to open it but resisted so far. My questions: Would a sealed bag from that period likely to have had the "good ones" culled out? Did banks just bag up 90% silver? Would this bag be of more value to a collector if I did not open it? To open, or not to open? That is the question. Thanks! Larry