Look under the green bottle, does it have a pontil scar ? Is it a push up blown in mold ? Does the brown bottle have any type of RX mark on it ? A lot of those brown bottles with measure increments contained chemicals. Also Lysol came in a similar bottle. A lot of medicine bottles with the measure increments were clear . Check the neck of your bottles, does the seam go all the way to the top ? I suspect the seam on the Dr. Kings bottle does not go all the way up. When the seam continues all the way up the bottle was made in an automatic bottle making machine. Other wise the older bottles are blown in mold type. BIM (blown in mold) ABM (automatic bottle machine) .. Open pontil , or pontil scarred (hand blown) ABM (newer) 1910's - present. BIM (older) 1870's -early 1900's . Pontil (oldest) 1860's and back. These figures are from memory to give you a general idea. Hope it helps. Also bottle prices fluctuate . If someone needs a certain bottle for their collection , they may be willing to pay a higher price to get it. Unfortunately the internet has flooded the market with 1000's of bottles . It is a great hobby , Bottle collecting and trading.