Hello, edzmaya.
Whether you're in Manila, Singapore, or any other city in the Western Hemisphere, you will have difficulty finding a pearl specialist to appraise your pearls. It would not be realistic to peg it to the going rate in the US and Europe (believe me, I tried).
For starters, you have to consider that the overhead cost in Palawan is much lower. As for quality, much of the pearls in the stores in Palawan are in the A to AA range. The high-end stuff are reserved for international auctions.
My experience with buying online, from Palawan-based vendors, has been mixed. My first pair was great, but succeeding purchases were of lesser quality. And if you bought yours from L's, she will always claim that her pearls are not dyed. That's why I prefer to buy in Greenhills; I can examine the pearls in person and the better merchants are more forthcoming.
Yours do not look dyed, but it's hard to tell from online photos. If you wish to add to your collection, I'm happy to accompany you to Greenhills and show you what to look out for.