No if it is for sale with a realtor, most investors will have already seen it listed on MLS, you can write a ton of offers for MLS properties to get them well below list price but you'll probably just annoy whoever is writing the offers because very rarely will they be accepted.
The value a wholesaler brings is finding properties that aren't available elsewhere if you just charge more for properties listed on MLS you are taking value away not adding it.
I would tend to agree with Aaron, wholesaling something off the MLS would be pretty tough because most investors would have seen it and that is just another set of fees you would be paying for closing etc.
I do think though that there are some good buy and hold or flip deals on the MLS and you should always keep your eye out for price drops or properties that have been sitting on the market for a long time. If someone's home has been on the market for half a year or longer they can become motivated especially if you are an all cash buyer that offers to close quickly. The strategy of sending the same person an offer monthly is something that has been talked about on podcasts and seems to work because you are constantly reaching out and putting a solution in front of that struggling owner. But finding a wholesale deal on the MLS would definitely be tough.
If you see a house that’s already for sale your to late.....