The gold labeled versions arose due to a change in Japanese li-on regulations....silver would therefore be older.
Bear in mind that it must be 6 years old at the very minimum and Li-on batteries do degrade as they age and not just as a factor of charge cycles.... have found a silver label one on ebay for 35 quid.. used but still working ok...
IIRC to charge the LP-E4N fully you need the matching charger otherwise they charge to 80% on the original charger for LP-E4 batteries.