@beeeerrun
Ahh not easily, no.
The code defined the post author as the vendor by author name still- so it still is using the username.
This code, which I am fairly sure is that which defines what you see in the selector box to assign a vendor, is found in the WC Vendors free file: wp-content/plugins/wcvendors/classes/admin/class-product-meta.php

public function author_vendor_roles( $output )
	{
		global $post;

		if ( empty( $post ) ) return $output;

		// Return if this isn't a WooCommerce product post type
		if ( $post->post_type != 'product' ) return $output;

		// Return if this isn't the vendor author override dropdown
		if ( !strpos( $output, 'post_author_override' ) ) return $output;

		$args = array(
			'selected' => $post->post_author,
			'id'       => 'post_author_override',
		);

		$output = $this->vendor_selectbox( $args );

		return $output;
	}

And no- I am not sure how to alter this properly at this time, but if you wish to give it a go, there’s the code that you would likely need to modify.