You can verify your Affiliate links using Amazon Link Checker, the free tool available in the Amazon Affiliate dashboard.
1. Import a product via Spreadr Plugin
2. Go to the imported product page on your WooCommerce store
3. Click on 'View on Amazon' button
4. The Amazon product page which opens in a new tab will have ?tag=yourAmazonTag-20 in the URL - this means your associate ID is embedded in the link and you will get credit for the sale.
4. Put the entire URL in the Amazon link checker. It will tell you whether the link is valid with your Affiliate ID.