Thank you for the request here.
Do the dolls have any tags or maker marks on them? Usually on the back or neck.
That is fine, definitely do no remove the clothing if the outfits are tightly affixed.
Your vintage souvenir girl and boy dolls from Holland in traditional Dutch clothing and shoes with decal affixed eyes with the other features hand painted measuring 18" each would sell for an average high of $50 - $80 for the pair together on today's market.
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Please let me know.