Sure I would. And I would also have them targetted by thieves wanted to redistribute the wealth, nobles wanting a piece of the pie, etc. No doubt the churches (esp if lawful) will want a tithe or contribution of some type. That much money will always attract thieves and others with an interest in gaining their "fair share."
I usually set up realistic rewards, but there are always consequences of some sort. Was it found on land within a kingdom? Even if it is not 'owned' by some noble, it is likely the king will want a slice of it. Was it the horde of a dragon or a bandit group? Likely it was stolen, and the ones it was taken from may still be alive to want it back - or their heirs.
If a PC walks into a bar to buy a drink, and pulls a gold coin from a bulging sack it is likely to be noticed. Local cutpurses will no doubt be in the area soon, as will burglars to inspect their rooms. If the settlement is large enough the thieves guild will know before long also. If they put it in a bank, they should be aware that banks that do not invest will charge for protecting the money, and those that do may run afoul of poor investments (sunken ships, lost caravans, gambling nobles they can't enforce to repay, etc).
In the long run it is best to convert to gems as soon as they can - or use it to buy readily carried equipment of one type or another. And be aware that if they enter town looking wealthy the taverns will likely charge an extra silver or gold (depending on their base quality), the local merchants may tac on a small extra fee, the local lords may make them aware of minor taxes they technically fall under, etc.
Wealth is both a boon and a bane, and the sooner they learn that the better. Note also that if they can afford better equipment, the ones that offer them quests may presume they are too experienced / skilled for the minor missions and go straight to giving them the harder missions.
Of course, what is really interesting are the new possibilities opened with the DMG2. If the players at second level use their wealth to open / invest in a shop, they might find a minor but notable source of wealth to last for some time to come. Of course, shops are also required to pay taxes the PCs typically do not - and may not be aware of.
If played right, a sudden surge in wealth can be just as campaign enriching (pun intended) and expanding as finding a new dungeon, exploring a new region, etc.
Hmm, you know, they could use that wealth to buy a ship (Stormwrack) and begin a high seas adventure, perhaps hiring a crew to sail for a distant port / land, etc.
