Mike,
Now that you mention it, I recall reading about several guns surfacing in the market with strange or missing serial numbers, and non-standard configurations, that were attributed to lunch box specials.
Johnny,
Congratulations on your new 547! I looked a long time for any 9mm revolver, and the 547 was the first one I found in excellent condition at a reasonable price.
Mike would know better than I about shooting it, but as a guess, I'd say keep it unfired if you want to keep the collector value up.
Mine had been fired before I bought it (though very little from all appearances), so I'm shooting it, but being extra careful with the extractor and finish.
Bill