What pieces are the hard ones to get for the McDonalds Monopoly game this year?

Here are the rare game pieces from this year's McDonald's Monopoly game:



Mediterranean Avenue prize - Stamp #251 - $100 - Purple

Vermont Avenue - Stamp #254 - $1,000 - Light Blue

Virginia Avenue - Stamp #258 - $2,000 - Maroon

Tennessee Avenue - Stamp #260 - $5,000 - Orange

Kentucky Avenue - Stamp #262 - $10,000 - Red

Ventnor Avenue - Stamp #266 - $25,000 - Yellow

Pennsylvania Avenue - Stamp #270 - $50,000 - Green

Boardwalk - Stamp #274 - $1,000,000 (annuity) - Blue

Short Line - Stamp #278 - $500 - Railroad

Golden Avenue - Stamp #271 - $100,000 - Gold

Water Works - Stamp #279 - $50 - WhiteWhat pieces are the hard ones to get for the McDonalds Monopoly game this year?
Today is Oct 9th and the game only started on Oct 7th, so it's a little early to tell (in my opinion). However, it appears to me that it's almost identical to the last time. You could probably make an assumption on the "rare" pieces based on previous experiences.