Yes, Solid Normal Tissue is one of the 'normal' tissues that were used in the TCGA. You can infer whether a sample is from tumour or normal by its TCGA barcode. The fourth (4th) component of the TCGA barcode, a 2-digit number, indicates this:

• Tumour samples: 01 - 09
• Normal samples: 10 -19
• Control samples: 20 - 29

Further information:

• A: Meaning letters in TCGA sample barcode field
• github.com/kevinblighe/TCGAbarcode/TCGAbarcode.pdf
• Sample Type Codes

If you don't have the TCGA barcodes and just have file UUIDs or filenames, then you can [possibly] obtain the matching TCGA barcodes for these via these functions:

• UUID-to-TCGA Barcode: C: Sample names for TCGA data from GDC-legacy archive
• Filename-to-TCGA Barcode: C: problem in matching the names between file names and patients Id in TCGA

Best of luck, Kevin