feeding bottles question

Hi Parents I have been using Dr Brown's feeding bottles, purple 8 oz plastic bottles for my baby, purchased from Amazon long time ago.

Previously, I purchased clear 5 oz bottles from Walmart and they were made in USA. I never realized to check these 8oz purple pack manufacturer for the big bottles.

There is a plastic material number 5 which i understand is polypropylene, serial number on the bottom and also number 5 on the vent for the 5 oz bottles( made in USA) I bought previously, but I don't see any number for the 8 oz bottles from Amazon.

Lately, while I was washing these bottles, I saw on the bottom of bottle they were Made in China, number 5 plastic and an SD number on the side of the bottle. There are also SD numbers 3, 4, 5, 6, 7, 8 on each part of the internal vents and straws. There is a plastic number 5 and China on the bottom and no serial number.

Now, I am worried if these bottles are real dr browns, if the material is same as those made in USA. I dont remember the packaging for these bottles from Amazon.

While I was checking my order history, it says Condition: New Sold by Amazon.com LLC services Don't have any shipped by details. With no shipment details, is it any third party seller?

Anyone using bottles ordered from Amazon and do you think they are fine?

Please help. Thanks