As Phil indicated, if it is still in the OFFER status. it still fair game. ANY new proposal can be considered and accepted over yours for any reason.
You indicated "No Papers Signed." That means any offer can displace yours.
The important factor is, Is yours an offer or a contract?
If you and the seller have agreed to all terms, conditions and price and both you and the seller have fully signed the purchase agreement, you not longer have an offer, but you do have a contract to buy. Until you reopen negotiations, you are secure in not being displaced. Ahh, but buyers do funny things and think they can do a price beat down later.
Be aware, although their may be a purchase contract in place, the seller will be lining up back up buyers who are hoping the engaged buyer goes goofy.
If you understand a financed buyer is not as attractive as a cash buyer, you may want to consider using a lender who can provide you a 'Clear-to-Close' before you go house shopping. This means you have passed the lenders underwriting and the bank has committed the money. You can close in days not months. This makes your purchase offer very competitive with cash offers. That should give a buyer greater confidence.
Even with this greater assurance, be aware, if it is not in writing it does not exist. Your REALTOR will be invaluable in positioning your purchase offer to be most beneficial to you.
Best of success.